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Ref NR/PS/SIG/11760Issue 1 Date December 2000

Westinghouse Signals FS2600 Track Circuits (formerly RT/E/PS/11760)

This temporary front sheet facilitates change to the new Network Rail Standards referencing nomenclature.

The Ref above will be formally allocated to this standard when it is next changed in the meantime the contents, date and issue number of this Network Rail Standard are UNCHANGED and with immediate effect it should be referred to as “(new ref) formerly (old ref)”.

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Uncontrolled copy once printed from its electronic source. Published & Issued by: Network Rail; 40 Melton Street, London NW1 2EE

RT/E/PS/11760Issue 1

December 2000

R A I L T R A C K L I N EP R O D U C T S P E C I F I C A T I O N

WESTINGHOUSE SIGNALSFS2600 TRACK CIRCUITS

Endorsement and Authorisation

Endorsed by:

A Simmons, Professional Head of Signalling

Accepted for Issue by:

This publication, includingthe data and informationrelating thereto, is not to beused, disseminated, stored ina retrieval system,reproduced, copied oradapted either in whole orin part without the expresswritten permission ofRAILTRACK plc.

Published & Issued byR a i l t r a c k p l cRai ltrack HouseEus ton SquareL O N D O NN W 1 2 E E

© 2000 RAILTRACK PLC

RT/E/PS/11760 RAILTRACK LINE PRODUCT SPECIFICATIONIssue 1December 2000Page 2 of 120 Westinghouse Signals FS2600 Track Circuits

Summary

This Line Specification states the minimum requirements for WestinghouseFS2600 track circuits. It includes lifecycle requirements from design, safety andenvironmental to installation, testing and maintenance.

Issue/Revision Record

Issue Date Comments1 December 2000 New Specification. The contents are based on Railway

Group Code of Practice GK/RC0760 which is to betransferred to Railtrack Line in February 2001.

Implementation

The requirements of this Specification shall apply to all Westinghouse SignalsFS2600 track circuits supplied for use on Railtrack controlled infrastructure onor after 3 February 2001. It shall also apply to the alteration and maintenance ofexisting Westinghouse Signals FS2600 track circuits from the same date. Thefollowing document is superseded:

Superseded Document

GK/RT0760, Issue 1, June 98 - Westinghouse Signals FS2600 Track Circuits

Disclaimer

Railtrack Plc has used its best endeavours to ensure that the content, layoutand text of this document is accurate, complete and suitable for its statedpurpose. It makes no warranties, express or implied, that compliance with thecontents of this document shall be sufficient to ensure safe systems of work oroperation. Railtrack plc will not be liable to pay compensation in respect of thecontent or subsequent use of this document for any purpose other than itsstated purpose or for any purpose other than that for which it was preparedexcept where it can be shown to have acted in bad faith or there has beenwilful default.

Supply

Paper copies of this document will be available by printing from electronic copyor, where this is not possible, may be issued on request to the DocumentController.

RAILTRACK LINE PRODUCT SPECIFICATION RT/E/PS/11760Issue 1

December 2000Westinghouse Signals FS2600 Track Circuits Page 3 of 120

ContentsPage

1 INTRODUCTION 71.1 Purpose 71.2 Scope 71.3 Introduction 7

2 APPLICATION AND CONSTRAINTS 82.1 Application 82.2 Constraints 82.2.1 General 82.2.2 Single Rail Track Circuits 92.2.3 Double Rail Track Circuits 10

3 FUNCTIONAL REQUIREMENTS 11

3.1 PRINCIPLES OF OPERATION 113.1.1 Transmitter 113.1.2 Receiver 113.1.3 Single Rail Track Circuit 113.1.4 Double Rail Track Circuit 123.2 BONDING REQUIREMENTS 133.3 OPERATING CATEGORY AND INTERFACE DELAY

REQUIREMENTS14

3.4 CHANNEL ALLOCATION 183.4.1 General 183.4.2 Examples of Channel Allocation 203.4.3 Permitted and Prohibited Layouts 21

4 PHYSICAL REQUIREMENTS 31

4.1 CABLING 314.2 WIRING DIAGRAMS 314.3 TRANSMITTER 364.4 RECEIVER 374.5 CAPACITORS 40

5 PERFORMANCE REQUIREMENTS 42

5.1 INSTRUMENTATION 425.2 SET-UP BOX 42


5.2.1 General Description 425.2.2 Construction 425.2.3 Interconnecting Cables 445.2.4 Functional Description 445.2.5 Functional Test 45

6 ENVIRONMENTAL REQUIREMENTS 52

6.1 ENVIRONMENTAL CONDITIONS 526.2 ENVIRONMENTAL RESTRICTIONS 526.3 ELECTROMAGNETIC INTERFERENCE

RESTRICTIONS52

7 SAFETY REQUIREMENTS 53

7.1 SYSTEM SAFETY 537.1.1 Exposed Terminals 537.1.2 Surge Arresters 537.1.3 Recommendation on Positioning of Track Relays 537.2 OCCUPATIONAL SAFETY 547.2.1 Protective Fusing 547.2.2 Insulation of Terminals 547.2.3 Safety Labelling 547.2.4 Safety Earthing 54

8 DESIGN REQUIREMENTS 55

8.1 SPECIAL DESIGN REQUIREMENTS 558.2 GENERIC DESIGN REQUIREMENTS 558.3 GENERIC DESIGN DELIVERABLES 558.4 RECORDING OF DEFICIENCIES 56

9 SPECIAL INSTALLATION PROCEDURES 57

9.1 CONVERSION OF A.C. TRACK CIRCUIT 579.2 TRANSMITTER 579.2.1 Tools and Equipment Required 579.2.2 Feed End Transformer Removal 579.2.3 FS2600 Transmitter Installation 589.3 RECEIVER 619.3.1 Tools and Equipment Required 619.3.2 VT1 Vane Relay Removal 619.3.3 FS2600 Receiver Installation 62



9.4 IMPEDANCE BOND TUNING CAPACITOR 649.4.1 Recommended Procedure for Capacitor Installation

on Howells Impedance Bonds65

9.4.2 Feed End and Receive End Impedance Bonds 659.4.3 Intermediate Impedance Bonds 67

10 SPECIAL TESTING PROCEDURES 70

10.1 INTRODUCTION 7010.2 TEST EQUIPMENT 7110.3 TRANSMITTER TEST 7210.3.1 Preparation 7310,3.2 Test Procedure 7310.4 TRANSMITTER IMPEDANCE BOND TEST 7410.5 INTERMEDIATE IMPEDANCE BOND TEST 7510.6 RECEIVE END IMPEDANCE BOND TEST 7510.7 RECEIVER SENSITIVITY SET-UP 7610.7.1 Receiver Sensitivity set-up Using set-up Box (Double

Rail)76

10.7.2 Receiver Sensitivity set-up Without set-up Box(Double Rail)

87

10.7.3. Set-up Procedure Completion 9310.7.4 Single Rail Track Circuits 9910.8 IRJ SHORTING TESTS 9710.8.1 IRJ Failure at Double Rail to Double Rail Abutment 9710.8.2 IRJ Failure at Double Rail to Single Rail Abutment 9810.8.3 IRJ Failure at Single Rail to Single Rail Abutment 9810.9 LIMIT TEST 9910.10 INTERFERENCE TESTS 100

11 SPECIAL MAINTENANCE PROCEDURES 100

11.1 INTRODUCTION 10011.2 ROUTINE EXAMINATION 10011.2.1 General 10011.2.2 Monitor Point Voltage Check 10011.3 DROP SHUNT TEST 10111.4 FULL TEST 10211.4.1 Transmitter Tests 102

11.4.2 Receiver Tests 10311.5 CORRECTIVE MAINTENANCE 10311.5.1 Maintenance Philosophy 10311.5.2 Transmitter Replacement 103


11.5.3 Receiver Replacement 104

12 SPECIAL FAULT FINDING PROCEDURES 106

12.1 INTRODUCTION 10612.2 FAULT FINDING PROCEDURES 10612.3 CAPACITOR TESTING 10612.4 TRANSMITTER LED INDICATIONS 10612.5 RECEIVER LED INDICATIONS 10712.6 IMPEDANCE BOND CHECK 10712.6.1 Tx End Impedance Bond 10712.6.2 Intermediate and Rx End Impedance Bond 10812.7 FAULT CHARTS 109

13 REFERENCES 113

14 GLOSSARY 114

APPENDIX A LIST OF COMPONENTS 115A.1 TRANSMITTER 116A.2 RECEIVER 116A.3 CAPACITOR FOR S2, S2A AND WH3 (WSL)

IMPEDANCE BONDS117

A.4 CAPACITOR FOR TYPE 3 (HOWELLS) IMPEDANCEBONDS

117

A.5 ADDITIONAL COMPONENTS 118A.6 OTHER EQUIPMENT AND TOOLS 118



1 INTRODUCTION

1.1 PURPOSE

This Product Specification gives details of best practice in respect ofWestinghouse Signals FS2600 track circuits in order to achieve the requirementsof RT/E/S/11752.

1.2 SCOPE

The contents of this Product Specification apply to FS2600 track circuits. Themore general requirements can be found in RT/E/S/11752. Safety issues specificto FS2600 applications are included; general safety issues are contained inRT/E/S/11752 and other relevant Railtrack standards.

1.3 INTRODUCTION

The FS2600 track circuit has been developed and manufactured by WestinghouseSignals Ltd. who own all intellectual rights to the FS2600 product. The contentsof this specification are based on information supplied by Westinghouse SignalsLtd. and incorporate subsequent Railtrack experience.

The FS2600 range of track circuit equipment is designed to replace existing VT1vane relay a.c. track circuits in d.c. electrified areas. The FS2600 system providesgreater immunity to traction current interference than the VT1 system itreplaces.

Some existing track circuits in d.c. traction areas are 50Hz a.c. type utilising VT1vane track relays, where the limits of each track circuit are defined by insulatedrail joints (IRJs). A transformer is used to inject a signal into one end of the trackcircuit and a phase-sensitive vane relay at the other end is held energised if thetrack circuit is unoccupied.

The FS2600 system replaces the feed transformer with a transmitter (Tx) and theVT1 relay with a receiver (Rx). Additionally, tuning capacitors are required toresonate the impedance bonds at the track circuit frequency of double rail trackcircuits.


2 APPLICATION AND CONSTRAINTS

2.1 APPLICATION

The application of FS2600 track circuits fulfils the basic requirement forcontinuous train detection.

Where additional integrity is required, e.g. for the operation of automatic levelcrossings (not locally monitored), they shall be used in conjunction with someother type of train detection device.

The use of FS2600 track circuits is only cost effective where their functionalcapabilities are of benefit, e.g. to give d.c. traction immunity.

2.2 CONSTRAINTS

FS2600 equipment is designed for use on single rail (see note in section 2.2.2)or double rail jointed tracks; in plain line and through switches and crossings(S&C), subject to the following constraints, in addition to the generalrestrictions given in RT/E/S/11752:

2.2.1 General

a) The minimum distance between FS2600 track circuits and 25kV a.c.electrified railway line shall be 3km.

b) Due to their very slow to pick-up characteristics, FS2600 track circuits havespecial interface delay requirements and limitations on minimum length.The Rx pick-up delay is 1290ms to 1685ms; the drop-away delay is 550msto 1000ms. Time delays must be considered during the design stage ofschemes utilising FS2600 track circuits. The rules to be applied are coveredin section 3.3.

c) There are proximity restrictions in the positioning of FS2600 track circuitequipment and cabling, due to interference. Details are given in section 6,Environmental Requirements.

d) FS2600 track circuit bonding shall not be wired in series with track circuitinterrupters. A separate relay circuit shall be provided in accordance withRT/E/PS/11764.

e) Restrictions exist for the application of the FS2600 system over levelcrossings due to inductive losses occurring with some level crossing surfaceunits. Refer to the Infrastructure Controller for guidance.



f) There are special restrictions when abutting with other types of trackcircuit, due to interference. In addition, IRJs are required on both rails.Since the sharing of a common rail with other types of track circuit isthereby precluded, interfaces within S&C layouts are not achievable. Theeffects of interference are minimised by the application of the followinglimitations:

g) The FS2600 system shall not be installed on any line where overlay trackcircuits are in use or on any line parallel to a line where they are in use.Note: 10kHz rail circuits are used extensively by London Underground.

h) FS2600 track circuits shall not abut Reed track circuits. An individual safetyassessment shall be made to justify the minimum distance between FS2600track circuits and Reed track circuits at each boundary. The assessmentshall be approved by the Railtrack Safety Assessment Panel.

i) An FS2600 channel 10 track circuit shall not abut a TI.21 frequency E trackcircuit and there shall be a minimum of two pairs of insulated rail jointsbetween track circuits using these channels on the same line.

j) An FS2600 channel 10 track circuit shall not be parallel to a TI.21frequency E track circuit unless there is one or more intervening trackbetween the relevant FS2600 and TI.21 track circuits. There shall not beany direct negative bonding connecting the relevant FS2600 and TI.21 trackcircuits.

k) An FS2600 channel 1 track circuit shall not abut a TI.21 frequency D trackcircuit and there shall be a minimum of two pairs of insulated rail jointsbetween track circuits using these channels on the same line.

l) An FS2600 channel 1 track circuit shall not be parallel to a TI.21frequency D track circuit unless there is one or more intervening trackbetween the relevant FS2600 and TI.21 track circuits. There shall not beany direct traction return bonding connecting the relevant FS2600 and TI.21track circuits.Note: Direct traction return bonding implies either a direct cableconnection from one track circuit impedance bond or resonant bond plateto another (or traction rail for a single rail track circuit) or a cableconnection via the negative busbar in a substation or track paralleling hut.

2.2.2 Single Rail Track Circuits

Note: At present, the use of FS2600 track circuits in single rail mode has notbeen approved. The guidance in this specification in relation to single rail trackcircuits is given for use when approval has been obtained. Any furtherconstraints applied as part of the approval shall also be applied.


a) Single rail track circuits may be between 18m and 200m in length, with amaximum spur length of 40m. The cable connecting the Rx to the rail maybe up to 300m long with a maximum loop resistance of 5Ω. The cableconnecting the Tx to the rail may be up to 120m long with a maximumloop resistance of 2Ω.

b) In electrified areas, double rail reed or TI.21 track circuits must not beallowed to be surrounded by an area of FS2600 single rail track circuits, e.g.on a loop line, as described in the appropriate Track Circuit ProductSpecification.

c) In electrified areas, traction return cross bonding must be provided at allinsulated rail joints (IRJs) in the traction return rail. The traction returnrails in adjacent terminal platforms shall also be bonded together at thebuffer stop end (see Part F of RT/E/S/11752).

d) In conductor rail electrified areas, protection boarding shall be fitted wherespecified in with Part C of RT/E/S/11752.

2.2.3 Double Rail Track Circuits

a) Double rail track circuits may be between 50m and 1200m long. The cableconnecting the Rx to the impedance bond may be up to 760m long with amaximum loop resistance of 12Ω. The cable connecting the Tx to theimpedance bond may be up to 150m long with a maximum loop resistanceof 2.5Ω

b) Double rail a.c. track circuits are not suitable for use in S&C.

c) Impedance bonds are always required for double rail track circuits inelectrified areas. FS2600 track circuits are not permitted for use in 50Hza.c. or dual electrified areas. General track circuit restrictions in electrifiedareas are given in RT/E/S/11752, but the following additional rules apply:

d) The minimum distance permitted between impedance bonds is 10m and themaximum distance is 800m (see RT/E/PS/1002 for traction cross bondingintervals).

e) Track circuits may contain not more than one intermediate impedancebond.

f) All impedance bonds must be fitted with a tuning capacitor as part of theFS2600 installation (see RT/E/PS/1002).



3 FUNCTIONAL REQUIREMENTS

3.1 PRINCIPLES OF OPERATION

3.1.1 TRANSMITTER

The Tx generates a frequency shift keyed (FSK) signal which is fed to the rails atone end of a track circuit. The Tx output is derived from three crystaloscillators; one of which provides a low frequency modulation signal, and theother two provide an upper and lower shift frequency. The modulationfrequency is used to switch the output between the upper and lower shiftfrequencies. Thus, the FSK waveform consists of the upper shift frequencyalternating with the lower shift frequency at a rate determined by themodulation frequency. The Tx maintains the output voltage within safe limits.

The FSK output at each of ten carrier frequencies is modulated by 15.6Hz.Three output voltage levels are available to suit the type of track circuit.

3.1.2 Receiver

The Rx is connected to the rails at the other end of the track circuit from theTx and carries out an analysis of the signal which it receives from the rails. Ifthe Rx determines that the signal is of correct form and sufficient level, thecircuit is proved clear and a twin-coil relay built into the Rx is energised. If thesignal is not of the correct FSK waveform or not above the threshold level, thetrack circuit is assumed to be occupied. The relay has four front contactswhich are closed to indicate that the track circuit is clear, and two backcontacts which are closed when the track circuit is occupied.

Note: Front and back contacts being open at the same time indicates aninternal fault in the Rx.

If there is a train in the track circuit, the axles provide a shunt path for thesignal so that the Rx receives a greatly attenuated input. The Rx thereforeallows the track relay to be de-energised and the circuit is considered occupied.Similarly, if there is a failure of the equipment, the track relay is de-energisedand again the track circuit is considered to be occupied.

3.1.3 Single Rail Track Circuit

Note: At present, the use of FS2600 track circuits in single rail mode has notbeen approved.

For single rail track circuits, the Tx output is fed directly to the rails via a15-20µF capacitor which blocks the d.c. traction current. Similarly, the Rx inputis connected to the rails via an internal 3.3µF capacitor as shown in Figure 1.


Figure 1

3.1.4 Double Rail Track Circuit

On double rail track circuits, the traction current by-passes the IRJs viaimpedance bonds, while the track circuit current is contained entirely withinthe limits of the track circuit. The track circuit signal from the Tx is passed tothe rails via an auxiliary coil on the impedance bond. A fixed value tuningcapacitor in the impedance bond terminal case is used to tune the auxiliary coilof the impedance bond to the operating frequency (i.e. the carrier frequency) ofthe track circuit. The peak impedance of the tuned impedance bond in isolationis approximately 13Ω. When installed in a track circuit, this impedance isreduced.

Similarly, at the other end of the track circuit, the signal from the rails is passedto the Rx via the auxiliary coil on the impedance bond. A capacitor is againincluded to tune the bond to the operating frequency. The centre tap of theimpedance bonds may be connected to the centre tap of impedance bonds onan adjacent track, or may be returned directly to the substation. A double railtrack circuit is shown in Figure 2.

Further information on impedance bonds is given in RT/E/PS/1002.



Figure 2

An intermediate impedance bond may be used either to balance the returncurrents in the two rails or to return current to the substation directly or viaan adjacent track. Again a capacitor is used to resonate the auxiliary coil at theoperating frequency of the track circuit.

3.2 BONDING REQUIREMENTS

The limits of FS2600 track circuits shall be defined by IRJs in at least one rail. Insingle rail mode, IRJs are provided in the insulated rail. In double rail mode, IRJsare provided in both rails. General details of bonding arrangements arecontained in RT/E/S/11752, the following being applicable to FS2600 trackcircuits:

The preferred configuration is double rail, implemented with series bonding onboth rails to traction standards.

Only where the double rail configuration is impractical, such as in S&C or shorttrack circuits, the single rail mode may be used. This shall preferably beimplemented with Standard series bonding on the insulated rail and parallelYellow traction bonding on the common rail (i.e. the traction return rail). Inthis mode, it shall be accepted that the traction rail bonding precludes detectionof rail breakage in the common rail. The special requirements for long spursare given in RT/E/S/11752.

Note: At present, the use of FS2600 track circuits in single rail mode has notbeen approved.


3.3 OPERATING CATEGORY AND INTERFACE DELAYREQUIREMENTS

A timing category has yet to be specified for the FS2600 track circuit.

a) When in an area controlled by a Free Wired or Geographical Interlocking(GEC or Westpac), unless restricted by another clause, the FS2600 trackcircuit may abut other track circuits as shown in Figure 3.

TRACK CIRCUIT COMPATIBLE BANNED(NON-COMPATIBLE)

FS2600FS2600FS2600 + 1 TPRTI.21HVIVT1 + 2 TPRs

VT1VT1 + 1 TPRCategory B*Category B* + 1 TPR

FS2600 + 1 TPRFS2600FS2600 + 1 TPRFS2600 + 2 TPRsTI.21HVIVT1(SP)VT1 + 2 TPRs

VT1VT1 + 1 TPRCategory B*Category B* + 1 TPR

FS2600 + 2 TPRsFS2600 + 1 TPRFS2600 + 2 TPRsVT1(SP)VT1(SP) + 1 TPRTI.21

All other combinations

* As defined in Part F of RT/E/S/11752

Notes: (1) The only TPRs to be considered are the BR933 type.

(2) The use of FS2600 with more than one TPR shall be avoided where it ispracticable to remove TPRs or on new installations.

Figure 3

b) The minimum length for any other combination of an FS2600 track circuitfollowing either a VT1(SP) or an FS2600 + 2 TPRs in a running directionshall be determined using the table in Figure 4.



PERMISSIBLE SPEED

(mph)

FS2600 FOLLOWING FS2600 + 2 TPRs Min. Length (metres)

FS2600 FOLLOWING VT1(SP) FS2600 + 1 TPR FOLLOWING VT1(SP) + 1 TPR FS2600 + 2 TPRs FOLLOWING VT1(SP) + 2 TPRs

Min. Length (metres)

FS2600 FOLLOWING VT1(SP) + 1 TPR FS2600 + 1 TPR FOLLOWING VT1(SP) + 2 TPRs

Min. Length (metres)

FS2600 FOLLOWING VT1(SP) + 2 TPRs Min. Length (metres)

100 125 152 179 206

90 110 137 161 185

80 95 122 143 165

70 79 106 125 144

60 64 91 107 123

50 49 76 89 103

40 34 61 72 82

30 19 46 54 62

20 N/A 30 36 41

15 N/A 23 27 31

10 N/A N/A N/A 21

Figure 4

c) If the combination is not covered by the tables in Figures 3 or 4, anindividual safety assessment is to be produced and recorded. The followingfactors need to be determined:

Number of slow to pick TPRs (BR933) for the VT1(SP) = SV

Number of slow to pick TPRs (BR933) for the FS2600 = SF

Number of additional repeat relays for the VT1(SP) = NV

Number of additional repeat relays for the FS2600 = NF

up to and including the first used in interlocking.

Note: Relays operated in parallel from the same contact count as one.

VT1(SP) transmission time = TV

FS2600 transmission time = TF

(i.e. the time taken for any transmission systems (FDM, TDM, etc.) tooperate. Usually, TV = TF for adjacent track circuits).


The time difference, T is calculated as follows:

T = (NV - NF) x 0.2 + (SV - SF) x 0.6 + 0.2 + (TV - TF)

The maximum speed (metres per second) that the train can pass over thetrack circuit is multiplied by T to obtain the minimum track circuit length(metres) for the FS2600 track circuit. A typical calculation is given as anexample:

A VT1(SP) track circuit has two TPRs (BR933) and three additional TPRsand is direct wired. An FS2600 has one TPR (BR933) and no additionalTPRs but is transmitted over an FDM system with a 0.3 second responsetime. This would give the following values:

SV = 2, SF = 1, NV = 3, NF = 0, TV = 0, TF = 0.3

Therefore; T = (3 - 0) x 0.2 + (2 - 1) x 0.6 + 0.2 + (0 - 0.3) = 1.7 seconds.

If maximum speed = 60mph (27 metres per second),

minimum length of FS2600 track circuit = 27 x 1.7 = 46 metres.

d) Where several track circuits are combined to form one longer track circuit,and the individual sections are not separately used for interlockingpurposes, these rules need not be applied to the individual sections althoughan assessment shall be made and recorded to ensure that at least onesection always remains occupied. The boundaries of the first and lastsection with adjacent track circuits are considered in the assessment.

e) When in an area controlled by Solid State Interlocking (SSI), unlessrestricted by another clause, the FS2600 track circuit (with or withoutextra delay data) may abut track circuits as shown in Figure 5. Theequivalent shall be determined for other data driven systems.



TRACK CIRCUIT COMPATIBLE BANNED

(NON-COMPATIBLE)

FS2600

FS2600FS2600 + extra delayVT1(SP)VT1 + extra delayTI.21HVI

VT1

Category B*

FS2600 + 1 TPR

FS2600FS2600 + extra delayVT1(SP)VT1(SP) + extra delayVT1 + extra delayTI.21HVI

VT1

Category B*

* As defined in Part F of RT/E/S/11752

Figure 5

f) In SSI areas, FS2600 track circuits without extra delay data may follow aVT1(SP) + “extra delay” when, in the direction of running, the FS2600 is nolonger than identified in Figure 6. The equivalent shall be determined forother data driven systems.

PERMISSIBLE SPEED

(mph)

FS2600 TRACK CIRCUIT FOLLOWINGVT1(SP) + “EXTRA DELAY”

Max. Length (metres)

100 224

90 201

80 179

70 156

60 134

50 112

40 89

30 67

20 45

15 34

10 22

Figure 6


3.4 CHANNEL ALLOCATION

3.4.1 General

A range of ten channels is available for the FS2600 system. The following rulesapply in allocating channels:

a) Consecutive track circuits must not be of the same channel except wherethe Txs abut and the two track circuits are either both single rail or bothdouble rail.

b) Cross bonded double rail track circuits are permitted provided one of thefollowing conditions is met:

• They are different channels

• They are the same channel and are cross bonded Tx to Tx

• They are the same channel and are cross bonded Rx or intermediatebond to Rx. The track circuit Rx bonded is less than 500m in lengthwithout intermediate impedance bonds.

• They are the same channel and are less than 500m in length and none ofthe cross bonded track circuits has an intermediate impedance bond.

Reference can be made to the layouts shown in Figure 16.

c) Intersecting tracks (as at bridges) if cross-bonded, must be treated as cross-bonded tracks described in b) above.

d) Where IRJ failure could cause energy from one track circuit to energiseanother of the same channel (even in the presence of a train shunt), thenprotection must be provided. This is by the use of detection pairs or,additionally for single rail track circuits, transpositions at the end of thetrack circuit. Detection pairs or transpositions indicate the leakage ofenergy past an IRJ by one or both track circuits in the pair failing right side.There must be at least two independent detection pairs or transpositionsbetween two track circuits of the same channel.

Note: A “detection pair” is a pair of FS2600 channels whose signalsare close together in frequency. If a signal from the Tx of one channel ofthe detection pair is detected by the Rx of the other channel, that Rx willde-energise the output relay. The pair is described as a “detection pair”because the effect is to detect failed IRJs.

A transposition is illustrated in Figure 7:



Figure 7

Channel numbers and detection pairs are shown in Figure 8:

CHANNEL CARRIER FREQUENCY(HZ)

DETECTION PAIRS

1 388.8 2, 3

2 403.2 1, 3, 4

3 417.6 1, 2, 4

4 432.0 2, 3

5 441.6 6, 7

6 456.0 5, 7, 8

7 470.4 5, 6, 8

8 484.8 6, 7

9 494.4 10

10 508.8 9

Figure 8

e) Where an FS2600 track circuit abuts a section of double rail jointless trackcircuit, ensure that none of the other extremities of the double rail jointlesssection abuts an FS2600 track circuit of the same channel. Where anFS2600 track circuit abuts a section of single or double rail jointed trackcircuit, one or both of the following must be ensured:

• None of the other extremities abuts FS2600 track circuits of the samechannel (except where two Txs are located together)

• At least two IRJs, whose failures are detectable, separate the FS2600track circuit from any other FS2600 track circuit of the same channel.

f) Track circuits of the same channel on parallel tracks must be separated byat least one other set of rails and, for double rail track circuits, must haveno more than 250m of parallelism. For single rail track circuits, there is nolimit on parallelism.


3.4.2 Examples of Channel Allocation

3.4.2.1 Plain Line

A typical channel allocation for plain line is shown in Figure 9:

Figure 9

3.4.2.2 Switches and Crossings

In Switches and Crossing (S&C) areas, a similar channel allocation is adopted tomaintain the sequence and comply with the rules given in this specification. Atypical allocation is shown in Figure 10:

Figure 10

A typical channel allocation for a more complex arrangement is illustrated inFigure 11:



Figure 11

3.4.3 Permitted and Prohibited Layouts

3.4.3.1 Double Rail Track Circuits

Note: In areas with three or more tracks, it is better to use a minimum ofthree intervening channels to avoid future problems with cross-bonding.

The following rules must be applied when allocating channels:

a) Before a channel may be repeated in a line of route, a minimum of twoother channels must intervene with at least two independent detectionpairs. Figure 12 shows permitted layouts:


Figure 12

Figure 13 shows two prohibited layouts:

Figure 13

b) For lateral channel repetition, at least one other set of rails must interveneand the maximum permitted parallelism is 250m. Track circuits which crossin the vertical plane at approximately right angles have no restriction.Figure 14 shows permitted layouts:



Figure 14

Figure 15 shows prohibited layouts:


Figure 15

a) No track circuit may be cross-bonded to a double rail track circuit of thesame channel except at Tx to Tx bonds or as described in section 3.4.1(b).Figure 16 shows permitted layouts.



Figure 16

3.4.3.2 Single Rail Track Circuits

Note: At present, the use of FS2600 track circuits in single rail modehas not been approved.


Note: The following rules apply over all possible directions whether there aresignalled movements over them or not:

a) Before a channel may be repeated in a line of route, a minimum of two otherchannels must intervene with at least two independent detection pairs ortranspositions at the end of the track circuit. Permitted layouts are shownin Figure 17:

Figure 17

A prohibited layout is shown in Figure 18:

Figure 18

b) A Tx may abut a Tx of the same channel at a single IRJ. Refer to section3.4.1(a).

c) For lateral channel repetition, at least one other set of rails must intervene.Track circuits which cross in the vertical plane at approximately right angleshave no restriction. Permitted layouts are shown in Figure 19:



Figure 19

A prohibited layout is shown in Figure 20:

Figure 20


3.4.3.3 Double Rail to Single Rail Track Circuits

Note: The preceding rules appertaining to double rail and single rail designsare to be applied on each side of the IRJs respectively, as shown in Figure 21:

Figure 21

The following rules must also be applied:

a) A Tx may not abut a Tx of the same channel at double rail to single rail IRJs.See Figure 22.

Figure 22

b) When a double rail area is restarted beyond a single rail area, irrespective ofthe track circuit designs within the single rail area, the double rail trackcircuits must ALL be of different channels unless the track circuits of thesame channel are fitted with Txs at the boundary. Permitted layouts areshown in Figure 23:



Figure 23

c) Two Txs may face each other at the double to single rail abutments, andmay be on different lines as shown in Figure 24:


Figure 24

d) A Tx may not face a Rx of the same channel across a junction. A prohibitedlayout is shown in Figure 25:

Figure 25

e) The channel allocation spacings in the double rail areas must be continuedwith the single rail area being totally ignored for this purpose.

3.4.3.4 Integration and/or Abutment with other Track Circuit Designs

The channel allocation is to be continued through the matrix of other designtrack circuits which are ignored for this purpose.



4 PHYSICAL REQUIREMENTS

4.1 CABLING

In lineside apparatus housings, wiring between tail cables and Txs or Rxs mustbe double insulated twisted pair cable, (max. 75mm pitch).

Tx and Rx tail cables must be 2c 2.5mm²(f) to RT/E/PS/00005.

4.2 WIRING DIAGRAMS

The following guidelines apply to all FS2600 wiring diagrams:

a) Lineside apparatus housing and equipment building layout drawings mustshow the position and channel of each Tx and Rx.

b) Lineside apparatus housing and equipment building wiring diagrams mustshow the connections to each Tx and Rx. In the case of the Rx, anadditional connection must be shown for an earth on terminal 36. All otherRx connections shall be unchanged from the VT1 relay, subject to contactallocation.

Note: Connecting an earth wire to the Rx and the Tx is desirable toensure reliable operation in the presence of transient interference. If anearth is not available, the earth terminal shall be connected to the rackingor the lineside apparatus housing metal work.

c) In the case of the Rx, the connections to the contacts shall be in accordancewith Figure 26.

CONTACT NUMBER & SYMBOL

13 14

23 24

33 34

43 44

15 16

45 46

36


Figure 26

d) In the case of the Tx, the connections shall be in accordance with Figure 27.

TX TERMINALS PURPOSE

12

Nominal Output Voltage 18 V for Single Rail Track Circuits

34

Nominal Output Voltage 100 Vfor Double Rail Track Circuits with NO Intermediate Bond

56

Nominal Output Voltage 200 Vfor Double Rail Track Circuits with an Intermediate Bond

7 Not Used

8 Voltage Adjustment Tap 115 V



11 Voltage Adjustment Tap Common

12 Not Used

13 Earth

14 BX110 Supply

15 NX110 Supply

Figure 27

e) The following “VT1” items are not required and shall be removed:

The adjustable capacitor from double rail track circuits, track resistors andtransient suppressor units which are connected across the vane relay inputson some track circuits and stabilising rectifiers which may be fitted to singlerail track circuits. An isolating transformer may be fitted between the tailcable fuse and the relay input on some track circuit installations. Thesetransformers are fitted at the discretion of the Infrastructure Controller toovercome excessive d.c. negative traction interference. They are notrequired for the FS2600 installation and are also to be removed.

f) All lineside apparatus housing wiring, including earth connections, shall be in0.75mm² Type A cable to RT/E/PS/00005 except where double insulatedtwisted pair cable is required for Tx and Rx connections.

g) Tail cables shall be 2c 2.5mm² (f) Type C cable to RT/E/PS/00005.



h) Surge arrestors must be mounted at the point at which the tail cables enteror leave a lineside apparatus housing or equipment building. Thebreakdown voltage for the surge arrestors shall be in the range 1200V to1800V d.c.

Typical wiring diagrams are shown in Figures 28 to 31:

Figure 28 shows the wiring diagram of the feed end of a double rail track circuitwith intermediate impedance bond:

Figure 28


Figure 29 shows the wiring diagram of the feed end of a double rail track circuitwithout intermediate impedance bond:

Figure 29



Figure 30 shows the wiring diagram for the Rx end of a double rail track circuit:

Figure 30


Figure 31 shows the wiring diagram for a single rail track circuit:

Figure 31

4.3 TRANSMITTER

The FS2600 Transmitter (Tx) is housed in a case 136.5mm (height) x 136.5mm(width) x 225mm (depth) and weighs 3.5 kg. The case comprises a steel shroudwith front and rear faces fabricated in pressure die cast aluminium. A carryinghandle is provided on the side of the front face. The Tx may be mounteddirectly to lineside apparatus housing racking or, via a bracket, on a woodenbackboard. All electrical connections for the Tx are made via a 15-way terminalblock on the front face of the Tx.



Figure 32 shows the Tx faceplate:

Figure 32

The faceplate of the Tx also contains two light emitting diode (LED) indicatorslabelled 'SUPPLY' and 'OUTPUT'.

The nominal power supply to the Tx is 110Va.c. 50Hz with voltage adjustmentterminals provided for a supply voltage between 88V and 121V. Maximumpower requirements are 60VA for single rail configuration and 80VA for doublerail configuration.

4.4 RECEIVER

The FS2600 Receiver (Rx) comprises a Rx electronic unit with an integralpower supply, and an integral twin relay similar to BR960 functioning as theTrack Relay. The Rx is housed in a case 215mm (height) x 160mm (width)x 280mm (depth) and weighs 9.6kg. It occupies a similar space envelope to aVT1 relay and plugs into a modified VT1 plug board on equipment racking. Thecase consists of an aluminium shroud with polycarbonate moulded front fascia.The unit is secured to the racking by means of a spring-loaded plunger, and isprovided with a retractable handle for ease of carrying andremoval/replacement. Connections to the Rx are made via contacts on the rearof the mounting base.


Figure 33 shows the Rx faceplate.

Figure 33

The faceplate of the unit contains six LED indicators labelled as shown in Figure34.

LED FUNCTION

Green 'SUPPLY

Red 'µP - A RUNNING'

Green INPUT - A VALID'

Red 'µP - B RUNNING'

Green 'INPUT - B VALID'

Red ‘OUTPUT'

Figure 34

The front face of the Rx also has two D-type connectors, one is a 15 way andthe other, a 9 way:



• A 15-way connector labelled 'SET UP.' During normal operation, this holdsthe configuration plug which consists of a plug, a hood and up to four links.One link sets the input for a single or double rail track circuit and up tothree links set the sensitivity of the Rx to the level required for the trackcircuit. During set-up procedure for a double rail track circuit, thisconnector is used to connect either the set-up box or, if no set-up box isavailable, a set-up plug. A label on the configuration plug is used to identifythe track circuit for which it has been set.

• A 9-way connector labelled 'MONITOR POINT.' This is used to connecteither a suitable meter or the set-up box during monitor point voltagechecks. It is blanked off during normal operation.

A window is provided on the front face of the Rx to allow the status andcondition of the track relay to be observed.

The nominal power supply to the Rx is 110Va.c. 50Hz with voltage adjustmentterminals provided for a supply voltage between 88V and 121V. The maximumpower requirement is 30VA.

To prevent a Rx of the wrong channel being inadvertently fitted to theplugboard, an interlocking system is used. Fifteen of the sixteen holes in thetop two rows of contact holes in the plugboard are blanked off and one is leftvacant. The position of the vacant hole depends on which channel Rx is to befitted. The details are given in Figure 35:


RX CHANNEL VACANTHOLE

(SEE NOTE)

POSITION OF VACANT HOLE ASSEEN FROM FACE OF

PLUGBOARD

1 81

2 82

3 71

4 72

5 61

6 62

7 51

8 52

9 41

10 42

Note: The interlocking hole identities are found on the rear of the plugboard.

Figure 35 (previous page)

4.5 CAPACITORS

All impedance bonds, whether intermediate or at the Tx or Rx end, must havean internal capacitor fitted, as described in section 9, Installation Procedures.



WARNING: High voltages may be present on impedance bond and othertrack circuit terminals. Extreme care must be taken when working on thisequipment.

Note: The FS2600 system must only be used with the impedance bondsspecified in Figure 36.

TYPE MANUFACTURER SPECIFICATION

WH3 Westinghouse Signals Ltd (WSL) 12959

S2 Westinghouse Signals Ltd (WSL) 12955

S2A Westinghouse Signals Ltd (WSL) 12955

3 Howells Ltd A10659 (Part No)

Figure 36

The capacitor chosen for each particular location depends on the channel ofthe track circuit and the type of impedance bond to which it is to be fitted.(See Appendix A, sections 3 and 4, for capacitors.) The value of capacitor doesnot depend on whether the impedance bond is at the Tx end, Rx end orintermediate, but the method of connection is different for intermediate bonds.

Note: Dependent upon the type of impedance bond, there are twoarrangements for the internal layout of the terminal block:

• Five or six in-line studs at one inch pitch (Westinghouse). See Figures 50and 52.

• Four studs arranged in a rectangle 33mm by 40mm (Howells). See Figures51 and 53.


5 PERFORMANCE REQUIREMENTS

General performance requirements are given in RT/E/S/11752.

5.1 INSTRUMENTATION

This section describes the set-up box which is designed for use in thecommissioning of FS2600 track circuits.

Details of other test instruments are given in Part N of RT/E/S/11752.

5.2 SET-UP BOX

5.2.1 General Description

The FS2600 set-up box (also referred to as the set-up test box) is a dedicatedportable item of test equipment for use in the commissioning of FS2600 doublerail track circuits. The FS2600 receiver (Rx) sensitivity is adjustable and the set-up box, in conjunction with a digital voltmeter (DVM) and a universal trackcircuit shunt box, enables the Rx to be set to the most appropriate sensitivityfor each track circuit.

The sensitivity of the Rx is configured by means of up to four wire linksconnected across pairs of pins in a 15-way D-type plug. This is called theconfiguration plug and is fitted into the set-up connector on the front of the Rx.When used on double rail track circuits, a test is carried out to determine therequired sensitivity and the appropriate wire links are fitted into theconfiguration plug.

Note: The FS2600 set-up box is not required for a Rx used on a single railtrack circuit. All single rail track circuit Rxs are set for the same sensitivity;therefore a pre-wired configuration plug is provided.

5.2.2 Construction

The set-up box has a moulded case which is fitted with a handle and a shoulderstrap. An area within the case is set aside for the storage of theinterconnecting cable.

The dimensions of the set-up box are as follows:

Length - 245mm

Width - 144mm

Height - 150mm



The weight of the unit, including the interconnecting cable, is 2.1kg.

Figure 37 shows the layout of the front panel:

Figure 37

The following components are mounted on the front panel:

• SET-UP Measurement Push button. This is a red topped push button which,when pressed, connects the ten-position potentiometer into themeasurement circuit

• Ten-Position Lockable Potentiometer (used to set the voltage shown on theDVM to the channel specific value). The locking mechanism is released bypulling the knob up, and locked by pushing it down

• Coarse, Medium and Fine Rotary Switches (used to configure the set-upbox to the required settings in order to test for the correct link settings fora particular sensitivity)

• LINK SET-UP Rotary Switch (used in conjunction with the LEDs todetermine which links are required)

• Twelve LEDs. These illuminate Green or Red during testing to indicatewhich links are required


• Two 'D' Type Connectors: A 25-way and a 15-way 'D' type connector areprovided. The 25-way is a plug connector (used for connecting the set-upbox to the Rx via the interconnecting cable). The 15-way is a socketconnector (used for inserting an unpopulated Rx configuration plug)

• Two Jack Sockets (SK1 and SK2) used to connect the DVM to the set-upbox.

5.2.3 Interconnecting Cables

An interconnecting cable is provided with the set-up box. One end isterminated in a 25-way 'D' type socket which connects into the 25-way plug onthe set-up box front panel. The other end terminates in two D typeconnectors; a 9-way socket which connects to the MONITOR POINT socketon the Rx, and a 15-way plug that connects to the SET-UP socket on the Rx.

Figure 38 shows the details of the interconnecting cable:

Figure 38

5.2.4 Functional Description

The set-up box is used in conjunction with a DVM, a universal track circuitshunt box and the tables provided in part F to determine the appropriatesensitivity setting of a Rx and its correct configuration plug link settings.



The Rx sensitivity is determined by setting the DVM reading to the appropriatechannel specific value, imposing a shunt into the circuit and recording theresultant reading. The tables provided in part F are then used to look up therequired settings which can then be obtained using the COARSE, MEDIUM andFINE rotary switches.

Once these switches are set, the set-up box is configured for the link positiontest.

The LINK SET-UP switch has five positions; SET-UP and four LINK positions (Ato D). The switch is set to position LINK A and two LEDs, one red and onegreen, illuminate to indicate where the link shall be fitted. If a link is notrequired, the NO LINK LED illuminates. When a link is fitted into its correctposition the LEDs are extinguished.

After the above procedure has been performed for each switch position(A to D) the configuration plug will have a minimum of two links and amaximum of four links if correctly set.

Full operating instructions for the set-up box are given in part F.

5.2.5 Functional Test

If a fault is suspected with the set-up box, or the results obtained using the set-up box are suspect, the interconnecting cable should be continuity tested byreferring to the wiring diagram shown in Figure 38. If the cable is correct,set-up box functional tests should be carried out as follows:

• All test results must be recorded

• If any one of the tests fail, the complete unit shall be deemed to have failed.

a) SET-UP

• Connect the 25-way socket of the interconnecting cable to the 25-way plugon the set-up box front panel

• Apply 15V ± 1.5Vd.c. @ 50mA from an external source across pin 9 (-ve)and pin 5 (+ve) of the 9-way socket of the interconnecting cable

• Set the LINK switch to the SET-UP position and check that no LEDs areilluminated.

b) LINK A

• Set the LINK switch to the A position


• With reference to Figure 39, check all switch permutations of the COARSE,MEDIUM and FINE rotary switches and ensure that the correct LEDsilluminate

• Connect the 15-Way plug (PL1) of the interconnecting cable into the15-way socket on the set-up box front panel and check that no LEDsilluminate for all permutations of COARSE, MEDIUM and FINE rotaryswitches

• Disconnect PL1.

Figure 39 shows the LED test states for LINK switch position A:

SWITCH POSITIONS AND LED INDICATIONS

COARSE MEDIUM FINE POSITION 1 FINE POSITION 2

LEDs ON LEDs ON

All Positions 1 4, 15 7, 4

All Positions 2 15,12 7, 12

All Positions 3 4, 15 7, 4

1 4 15, 13 7, 13

2 4 6, 15 7, 6

3 4 15, 13 7, 13

4 4 8, 15 8, 7

5 4 6, 15 7, 6

6 4 15, 14 7, 14

7 4 15, 14 7, 14

All positions 5 15, 12 7, 12



Figure 39

c) LINK B

• Set the LINK switch to the B position.

• With reference to Figure 40, check all switch permutations of the COARSE,MEDIUM and FINE rotary switches and ensure that the correct LEDsilluminate.



• Connect the 15-Way plug (PL1) of the interconnecting cable into the15-way socket on the set-up box front panel and check that no LEDsilluminate for all permutations of COARSE, MEDIUM and FINE rotaryswitches.

• Disconnect PL1.

Figure 40 shows the LED test states for LINK switch position B (extends overtwo pages):


COARSE MEDIUM FINE POSITION 1 FINE POSITION2

LEDs ON LEDs ON

1 1 5, 13 5, 13

2 1 5, 6 5, 6

3 1 5, 13 5, 13

4 1 8, 5 8, 5

5 1 6, 5 6, 5

6 1 5, 14 5, 14

7 1 5, 14 5, 14

7 2 5, 14 5, 14

6 2 5, 14 5, 14

5 2 6, 5 6, 5

4 2 8, 5 8, 5

3 2 5, 13 5, 13

2 2 5, 6 5, 6

1 2 13, 5 13, 5

1 3 13, 12 13, 12

2 3 12, 6 12, 6

3 3 13, 12 13, 12

4 3 12, 8 12, 8

5 3 6, 12 6, 12

6 3 14, 12 14, 12

All Positions 4 No Link No Link

7 3 14, 12 14, 12



COARSE MEDIUM FINE POSITION 1 FINE POSITION2

LEDs ON LEDs ON

7 5 4, 14 4, 14

6 5 4, 14 4, 14

5 5 6, 4 6, 4

4 5 8, 4 8, 4

3 5 4, 13 4, 13

2 5 6, 4 6, 4

1 5 4, 13 4, 13

1 6 13, 12 13, 12

2 6 6, 12 6, 12

3 6 13, 12 13, 12

4 6 8, 12 8, 12

5 6 6, 12 6, 12

6 6 14, 12 14, 12

7 6 14, 12 14, 12

7 7 4, 14 4, 14

6 7 4, 14 4, 14

5 7 6, 4 6, 4

4 7 8, 4 8, 4

3 7 4, 13 4, 13

2 7 6, 4 6, 4

1 7 4, 13 4, 13

Figure 40

d) LINK C

• Set the LINK switch to the C position

• With reference to Figure 41, check all switch permutations of the COARSE,MEDIUM and FINE rotary switches and ensure that the correct LEDsilluminate



• Connect the 15-Way plug (PL1) of the interconnecting cable into the 15-way socket on the set-up box front panel and check that no LEDs illuminatefor all permutations of COARSE, MEDIUM and FINE rotary switches

• Disconnect PL1.

Figure 41 shows the LED test states for LINK switch position C (extendsover two pages):


COARSE MEDIUM FINE POSITION1

FINE POSITION2

LEDs ON LEDs ON

1 1 8, 14 8, 14

2 1 8, 14 8, 14

3 1 8, 6 8, 6

4 1 No Link No Link

5 1 8, 13 8, 13

6 1 8, 6 8, 6

7 1 8, 13 8, 13

7 2 8, 13 8, 13

6 2 8, 6 8, 6

5 2 8, 13 8, 13

4 2 No Link No link

3 2 8, 6 8, 6

2 2 8, 14 8, 14

1 2 8, 14 8, 14

1 3 8, 14 8, 14

2 3 8, 14 8, 14

3 3 8, 6 8, 6

4 3 No Link No Link

5 3 8, 13 8, 13

6 3 8, 6 8, 6

7 3 8, 13 8, 13

7 4 8, 13 8, 13

6 4 8, 6 8, 6




FINE POSITION2

LEDs ON LEDs ON

5 4 8, 13 8, 13

4 4 No Link No Link

3 4 8, 6 8, 6

2 4 8, 14 8, 14

1 4 8, 14 8, 14

1 5 8, 14 8, 14

2 5 8, 14 8, 14

3 5 8, 6 8, 6

4 5 No Link No Link

5 5 8, 13 8, 13

6 5 8, 6 8, 6

7 5 8, 13 8, 13

7 6 8, 13 8, 13

6 6 8, 6 8, 6

5 6 8, 13 8, 13

4 6 No Link No Link

3 6 8, 6 8, 6

2 6 8, 14 8, 14

1 6 8, 14 8, 14

1 7 8, 14 8, 14

2 7 8, 14 8, 14

3 7 8, 6 8, 6

4 7 No Link No Link

5 7 8, 13 8, 13

6 7 8, 6 8, 6

7 7 8, 13 8, 13

Figure 41



e) LINK D

• Set the LINK switch to the D position.

• With reference to Figure 42, check all switch permutations of the COARSE,MEDIUM and FINE rotary switches and ensure that the correct LEDsilluminate.

• Connect the 15-Way plug (PL1) of the interconnecting cable into the15-way socket on the set-up box front panel and check that no LEDsilluminate for all permutations of COARSE, MEDIUM and FINE rotaryswitches.

• Disconnect PL1.

Figure 42 shows the LED test states for LINK switch position D:



FINE POSITION 2

LEDs ON LEDs ON

All Positions All Positions 1, 9 1, 9

Figure 42


6 ENVIRONMENTAL REQUIREMENTS

6.1 ENVIRONMENTAL CONDITIONS

All equipment associated with FS2600 track circuits shall conform tospecification BR967, category D, and, in addition, track-mounted equipmentshall conform to BR967, category F.

6.2 ENVIRONMENTAL RESTRICTIONS

A space of 30mm must be allowed all around the Tx for ventilation purposes.

6.3 ELECTROMAGNETIC INTERFERENCE RESTRICTIONS

Tail cables for track circuits of the same channel must not be run in parallel fordistances greater than 200m.

The housing of FS2600 equipment shall be restricted as follows:

• The lineside apparatus housing shall not contain any CCTV equipment, (thisincludes driver-only operation equipment). Refer to section 10.10 oncross-talk tests.

• An FS2600 channel 10 Tx shall not be located in the same lineside apparatushousing or equipment building as a TI.21 frequency E Rx.

• An FS2600 channel 1 Tx shall not be located in the same lineside apparatushousing or equipment building as a TI.21 frequency D Rx.

• Cables to FS2600 equipment within equipment buildings shall not be laid inany ducting or routing with cables of any other equipment. The FS2600cable routes shall be located to give maximum separation from existingcable routes (a minimum separation of 100mm where the total length ofparallelism is less than 2m or a minimum separation of 1m where the totallength of parallelism is more than 2m). A total length of parallelism whichexceeds 10m is not permitted. The location of FS2600 cable routes shall berecorded on record drawings.

• All vital Reed FDM system wiring must be in twisted pair cables (maximum75mm pitch).



7 SAFETY REQUIREMENTS

7.1 SYSTEM SAFETY

The following features are fully described elsewhere in this specification:• The FS2600 track circuit provides the safety integrity required in

RT/E/S/11752, including operation by lightweight vehicles.• To guard against bond failure causing a vehicle to go undetected, series

bonding shall be used wherever practicable. Where impracticable over alength likely to lose a vehicle, yellow bonding must be applied as a mitigationmeasure, as explained in RT/E/S/11752.

• Some delay must be incorporated into FS2600 track circuit clearance timesand, where necessary, the minimum length of track circuits restricted, so asto prevent a fast moving train being lost between track circuits.

• Where necessary, mitigation measures must be taken to preventinterference between adjacent track circuits.

• Where susceptible to electromagnetic interference, immunity must beachieved, if necessary by physical separation.

• Where mounted in the vicinity of safety-related equipment susceptible toelectromagnetic interference, proximity rules must be followed.

7.1.1 Exposed Terminals

Exposed terminals must be prevented from making electrical contact withother terminals where there is a risk of a component becoming loose or toolsbeing dropped. The preferred method is by shrouding.

7.1.2 Surge Arresters

Surge arresters must not be earthed because of the danger from multiple earthfaults caused by a traction fault or lightning strike.

7.1.3 Recommendation on Positioning of Track Relays

Electrical isolation between track cables and the interlocking environment isdesirable. Consequently, track relays and track feeds shall generally be confinedto lineside locations with repeat relays provided in interlockings.


7.2 OCCUPATIONAL SAFETY

Special precautions shall be taken to protect personnel from the high voltagespresent on impedance bond coils and other terminals, as well as from tractionvoltages under fault conditions, including fusing, insulation, labelling and earthing.These shall generally be based on BS 7671.

7.2.1 Protective Fusing

A fuse, preferably fully enclosed to BS 88, is to be provided in the apparatushousing in one leg of the track cables (both Tx and Rx end), as protectionagainst traction faults, as follows:• Single rail track circuits shall be fused in the insulated rail leg.• Double rail track circuits shall be fused in the leg connecting to the

impedance bond winding.

The removable carrier in the other leg shall be fitted with a shrouded link.

7.2.2 Insulation of Terminals

Track circuit tail cable terminations shall be fully shrouded or situated indedicated enclosures, as described in Code of Practice RT/E/C/11600. Theterminals of all track circuit equipment shall be shrouded or enclosed, exceptwhen using the safety procedures for work on electrical equipment.

The shrouding can take the form of a transparent Perspex sheet, which isremovable for maintenance purposes.

7.2.3 Safety Labelling

Due to the high voltage present on FS2600 track circuits, it is necessary toinstall warning signs to equipment, as shown in Figures 28 to 30, and on theoutside of all lineside apparatus housings containing track circuit equipment.

The "Caution, risk of electric shock" warning signs depict a yellow triangle withlightning flash, as described in RT/E/S/11752, Part J.

7.2.4 Safety Earthing

The standard rules for earthing apparatus housings and class 1 equipment shallbe followed, with all earth bonding shown on the wiring diagrams.

This earthing invariably requires a lower impedance than any requirement forFast Transient Earthing, which is desirable to protect transmitters and receiversfrom transient interference, as detailed in section 9, Installation Procedures.

Earth wiring must be as short and straight as practicable.



8 DESIGN REQUIREMENTS

8.1 SPECIAL DESIGN REQUIREMENTS

There are no special design requirements other than those given in thepreceding rules.

8.2 GENERIC DESIGN REQUIREMENTS

The generic design requirements in RT/E/S/11752 include:• interfaces with authorised rail vehicles (immunity, track circuit shunt

capacity, positioning of IRJs, minimum track circuit lengths, which may bedependent on permissible speed, and interlocking measures to mitigateagainst any deficiencies),

• interfaces with the permanent way (IRJs, standard rail bonding with pre-drilling requirements and S&C bonding configuration),

• interfaces with the electric traction infrastructure (immunity, single ordouble rail configuration and impedance bond positioning),

• interfaces with the interlocking system (operating times and measures tomitigate against false release of interlocking when there is a significant risk),

• the requirement for secure power supplies.

8.3 GENERIC DESIGN DELIVERABLES

The design deliverables associated with track circuits that are specified in theSignalling Design Handbook (Code of Practice RT/E/C/11701) include:• signalling/scheme plan,• control tables,• track circuit schedule,• location area plan,• bonding plan (or track plan),• interlocking layout and wiring, and• location layout and wiring.

All channel numbers shall be shown on signalling/scheme plans (when allocated),location area plans and bonding/track plans.

Plan symbols shall conform to RT/E/C/11004.


8.4 RECORDING OF DEFICIENCIES

In addition to the above, the designer shall record the following deficiencies onthe signalling plan or bonding plan, as advised by testers, installers ormaintainers:

• any critical or sub-standard clearances at S&C, dimensioned to fouling point.



9 SPECIAL INSTALLATION PROCEDURES

These Procedures shall be read in conjunction with Part J of RT/E/S/11752 andthe Signalling Installation Handbook.

WARNING: High voltages may be present on impedance bond andother track circuit terminals. Extreme care must be taken whenworking on this equipment.

WARNING: No cross-connection shall occur between Reed FDMand FS2600 equipment.

9.1 CONVERSION OF A.C. TRACK CIRCUIT

The following procedures describe the conversion of a 50Hz a.c. track circuit,equipped with a VT1 style vane relay, to a FS2600 track circuit:

9.2 TRANSMITTER

The Tx replaces the feed transformer of the 50Hz VT1 track circuit system.The following sections describe the procedure for disconnecting and removingthe transformer and installing and connecting the FS2600 Tx:

9.2.1 Tools and Equipment Required

• Tx mounting assembly (WSL part no. J22763/1)

• Key for lineside apparatus housing

• Installation copies of the site wiring diagrams

• Train Detection Manual

• Signalling Technician’s Tool Kit

• Fuse Extractor

• Crimp tags (AMP Part No 150730, WSL stock code 61239596).

9.2.2 Feed End Transformer Removal

Remove and retain the transformer power supply fuse and the track circuit fuseusing the fuse extractor. For single rail track circuits, also remove and retainthe track feed link.

Ensure that the wires to the transformer are all clearly labelled to facilitatereconnection. Disconnect all wires from the transformer terminal block.Disconnect the earth wire (if fitted) from the transformer frame.


Note: These transformers may be fitted either on equipment racking or on awooden backboard.

Where the transformer is fitted on equipment racking, remove the fixing nutsand washers from the transformer mounting studs and remove it from theracking. Remove the transformer adaptor plate. Where the transformer isfitted on a wooden backboard, remove the woodscrews which secure thetransformer and remove it.

9.2.3 FS2600 Transmitter Installation

Ensure that the Tx is the correct channel for the site.

Check that the sealing plugs (fitted to detect unauthorised access) are intact andundamaged.

Note: The plugs are fitted in the top and bottom of the front and rear faces ofthe Tx. The plugs on the front face are behind the blanking plates. They can bechecked by removing the top and bottom blanking plates using a smallscrewdriver. The blanking plates can be clipped back into place after checking.

Refer to Figure 32 for a view of the Tx faceplate and blanking plates.

A Tx may be fitted either on equipment racking using fixing screws andwashers, or onto a wooden backboard via a Tx mounting assembly (WSL partno. J22763/1).

For backboard mounting, fit the mounting bracket to the wooden backboardusing woodscrews through the four holes in the bracket. The bracket ismounted as shown in Figure 43:

Figure 43



Fit the four shouldered screws complete with shakeproof washers to the holesin the rear of the Tx. Ensure that the blanking plates are fitted over the unusedmounting holes in the front face of the Tx and fit the Tx to the mountingbracket by sliding the four shouldered screws down the slots on the bracket.Refer to Figure 44.

Figure 44

For mounting on equipment racking, the Tx may be mounted via tapped holesin either the front or rear face depending on whether the unit is to be front orrear mounted. Fit the blanking plates over the unused holes. Figure 45 showsthe arrangement for rear mounting.

Fit the Tx in the appropriate position and secure in place with the four M5screws provided, fitting a flat washer and spring washer onto each screw asshown in Figure 45.

CAUTION: To prevent damage to the Tx, use only the M5 10mm screwsprovided with the unit. Under no circumstances must longer screws be used.


Figure 45

Note: When making electrical connections to the Tx, care must be taken toview the unit “straight on” as a parallax error may arise if viewed at an angle.

Ensure that the short link provided with the Tx is connected between terminals8 and 11.

Crimp a termination pin to each of the four wires removed from thetransformer and connect the four wires to the terminal block on the Tx inaccordance with the site wiring diagrams.

Crimp a termination pin to the earth wire and connect to the earth terminal(13) on the Tx in accordance with the site wiring diagrams.

Note: When making crimped connections, the correct crimping tool must beused.

Note: Connecting an earth wire to the Tx is desirable to ensure reliableoperation in the presence of transient interference. If an earth is not available,then the earth terminal should be connected to the racking or the linesideapparatus housing metalwork.



9.3 RECEIVER

The Rx replaces the vane relay in the VT1 track circuit system. It is a directexchange and no wiring changes are required at the Rx mounting base otherthan the provision of an earth wire. The following sections describe theprocedure for disconnecting and removing the vane relay and installing andconnecting the FS2600 Rx.

Note: The Rx uses the full depth across all its height and therefore mayrequire alterations to existing VT1 mountings in some cases to avoid foulinglock mechanisms and roof lips of lineside apparatus housings.

9.3.1 Tools and Equipment Required




• Signalling Technician's Tool Kit

• Fuse Extractor

• Relay/Rx Release Tool (WSL part no. B48259/1)

• Rectangular Interlocking Plug Removing Tool (WSL part no. J22768/1).

Note: The Rx is supplied with the following:

• 15-way blank configuration plug for use on double rail track circuits

• Five wire links (four for use with blank configuration plug plus one spare)

• Rx base conversion kit (WSL part no. J22762/1).

9.3.2 VT1 Vane Relay Removal

The vane relay is mounted on a plugboard on the equipment racking. Alloperational connections are made via contacts on the plugboard. To remove avane relay, proceed as follows:

Remove the local coil supply fuse and the tail cable fuse using the fuseextractor. For single rail track circuits, also remove the track feed link.

Remove the track circuit label from the relay (if fitted) and retain it to fit to theRx.


Grasp the relay support handle with one hand to prevent the unit fallingforwards when the lock plunger is released.

Refer to Figure 46. Lift the lock plunger to disengage the lock and allow therelay to move slightly forward just enough to prevent the lock plunger re-engaging.

Still holding the handle with one hand, support the relay with the other handand withdraw it from the plugboard by pulling it forwards.

Figure 46

9.3.3 FS2600 Receiver Installation

Figure 33 shows the Rx faceplate.

Remove any existing plugboard labels and clean off the surface using the swabs.

Gently drive the round plastic plug into the round interlocking hole in theplugboard until the plug is almost flush and the Rx fits the plugboard.

Figure 47 shows the plugboard converted for Rx mounting.

Note: To prevent a Rx of the wrong channel being inadvertently fitted to theplugboard, an interlocking system is used. Fifteen of the sixteen holes in thetop two rows of contact holes in the plugboard are blanked off and one is leftvacant. The position of the vacant hole depends on which channel Rx is to befitted.



Check which channel Rx is to be fitted and refer to Figure 35 and Figure 47 todetermine which interlocking hole is to be left vacant. Push the fifteenrectangular interlocking plugs to the top two rows of contact holes in theplugboard face leaving the channel number hole clear. Ensure that each of therectangular interlocking plugs is correctly locked into place. If an error is made,the incorrect plug should be removed with a blanking plug removal tool.

Caution: The plugboard holes use the existing plugboard terminal numberingsystem, therefore it is vital to refer to Figure 35 and Figure 47.

Figure 47

Select the appropriate labels for the Rx channel and affix to the plugboard asshown in Figure 47.

Connect an earth wire to terminal 36 of the Rx plugboard in accordance withthe lineside apparatus housing wiring diagrams.

Note: Connecting an earth wire to the Rx is desirable to ensure reliableoperation in the presence of transient interference. If an earth is not available,terminal 36 should be connected to the racking or the lineside apparatushousing metalwork.

Ensure that the Rx power supply fuse and track fuse are removed.

Ensure that the Rx is the correct frequency for the location and check that itssealing plugs are intact and undamaged.

Note: The plugs are fitted on the rear of the Rx to deter unauthorised accessby protecting the screws that secure the handle. See Figure 48.


If a track circuit label was removed from the vane relay, fix it to the Rx.

Support the base of the Rx with one hand and grasp the handle with the otherhand. Push the Rx straight back onto its plugboard and ensure that the lockplunger engages.

Push the sliding handle back to the stowed position.

Figure 48

9.4 IMPEDANCE BOND TUNING CAPACITOR

All impedance bonds, whether intermediate or at the Tx or Rx end, must havean internal capacitor fitted as part of the FS2600 installation.

The only permitted types of impedance bond for FS2600 installation arespecified in Figure 36.

See Appendix A, sections 3 and 4, for details of capacitors.





• Five or six in-line studs at one inch pitch (Westinghouse)

• Four studs arranged in a rectangle 33 mm by 40 mm (Howells).

9.4.1 Recommended Procedure for Capacitor Installation onHowells Impedance Bonds

Note: As there is restricted space in Howells impedance bond auxiliary coilterminal blocks, capacitors must be fitted as follows:

• The cable entry gland on the left hand side of the terminal compartmentMUST be shortened so as to be flush on the inside of the auxiliary coilcompartment in order to allow the capacitor to be fitted.

• Fit the capacitor by firstly removing all nuts, washers and connectors fromthe two studs on which the capacitor is to be fitted (see Figures 51 and 53).Fit one washer on each stud, then the capacitor, then replace the remainingnuts, washer and connectors as shown in Figure 49.

Figure 49


9.4.2 Feed End and Receive End Impedance Bonds

Figures 50 and 51 show typical wiring layouts for the two arrangements ofterminal block.

Note: Before fitting capacitors to Howells impedance bonds, refer to section9.4.1.

At feed (Tx) end and receive (Rx) end impedance bonds, the capacitor isconnected in series with the auxiliary coil as follows:

• Ensure that the capacitor is the same channel as the track circuit and iscorrect for the type of impedance bond. (See Appendix A, sections 3 and 4,for capacitors.)

• Remove the impedance bond auxiliary coil terminal cover

• Alter the wiring in the terminal block so that the capacitor is in series withthe Tx (or Rx) and the auxiliary coil. Figure 50 shows an example of howthe wiring is modified in a terminal block with five (or six) studs(Westinghouse). Figure 51 illustrates the change in a four stud (Howells)terminal block.

Figure 50



Figure 51

Note: The phasing of the impedance bond is altered by interchanging the cableand rail connection wires between A and B in Figures 50 and 51. Refer tosection 10, Testing Procedures for details of bond phasing and operation. Tofacilitate alteration of impedance bond phasing, place the cable and railconnections uppermost on terminals TC and T0.

• Ensure that all cable glands are correctly fitted and that a 3mm dia. drainhole is drilled in the bottom of the auxiliary coil chamber.

• Refit the impedance bond auxiliary coil terminal cover.

• To ensure that the tuning capacitor does not foul the cables emerging fromthe cable glands, it shall be placed on the auxiliary coil side of the terminalsas shown in figure 50.

9.4.3 Intermediate Impedance Bonds


• Five or six in-line studs at one inch pitch (Westinghouse)

• Four studs arranged in a rectangle 33 mm by 40 mm (Howells).


Caution: Before fitting capacitors to Howells impedance bonds, refer tosection 9.4.1.

At intermediate impedance bonds, the capacitor is connected in parallel withthe auxiliary coil and is fitted as follows:

• Ensure that the capacitor is of the correct channel and is correct for thetype of impedance bond. (See Appendix A, sections 3 and 4, for capacitors.)

• Remove the impedance bond auxiliary terminal cover.

• Connect the capacitor for the FS2600 installation across the auxiliary coil asshown in Figure 52 for terminal blocks with five or six studs(Westinghouse), or Figure 53 for terminal blocks with four studs (Howells).

Figure 52

Figure 53



• Ensure that all cable glands are correctly fitted and that a 3mm dia. drainhole is drilled in the bottom of the auxiliary coil chamber.

• Refit the impedance bond auxiliary coil terminal cover.


10 SPECIAL TESTING PROCEDURES

10.1 INTRODUCTION

These Procedures shall be read together with the general information in Part Kof RT/E/S/11752. Only specific instructions applicable to FS2600 track circuitsare covered in this part.


WARNING: No cross-connection shall occur between Reed FDM andFS2600 track circuit equipment.

Throughout the setting-up procedure, details of all readings shall be recordedon a track circuit maintenance record card to establish a set of originalreadings. If the specified voltage or current figures are not obtainable in thesetests, refer to section 12, Fault Finding Procedures, for advice.

If FS2600 track circuits are installed on any section of line which passes anydriver-only operation CCTV equipment, the CCTV must be observed beforeand after conversion to FS2600 track circuits for any interference to thepicture. If quality is reduced to an unacceptable level, the CCTV is to beswitched off and reported to Railtrack Control until the picture quality can beimproved.

The following action must be taken in all cases where Reed FDM equipmentexists in the same locality as FS2600 track circuits:

Reed FDM cable insulation shall be tested to ensure a minimum insulationresistance to earth of 10MΩ from each cable core at or before commissioningof the FS2600 equipment and thereafter on a regular basis (periodically 12weeks for vital systems or 52 weeks for non-vital systems) on any segment ofthe Reed FDM system where:

• There is Reed FDM equipment in the same lineside apparatus housing orequipment building as the FS2600 track circuit equipment

• The FS2600 tail cables share the same cable route as the Reed FDM cables

• The Reed FDM cable route is parallel to the FS2600 track circuit.

If any section of cable has a minimum insulation resistance to earth of less than10MΩ, the appropriate procedure shown in Figure 54 is necessary:



INSULATIONRESISTANCE

VITALREED SYSTEM

NON-VITALREED SYSTEM

LESS THAN 1MΩ IMMEDIATE CORRECTIVE ACTION(WITHIN 1 WEEK)

EARLY CORRECTIVEACTION(WITHIN ONE MONTH)

1MΩ - 3MΩ EARLY CORRECTIVE ACTION(WITHIN 1 MONTH)

PROGRAMMEDCORRECTIVE ACTION(WITHIN ONE YEAR;MONITOR EVERY 12WEEKS)

3MΩ - 6MΩ PROGRAMMED CORRECTIVE ACTION(WITHIN 1 YEAR)

MONITOR EVERY 12WEEKS

6MΩ - 10MΩ MONITOR EVERY 12 WEEKS MONITOR EVERY 52WEEKS

Figure 54

10.2 TEST EQUIPMENT

The following items of test equipment are required:

• Digital Voltmeter (DVM), Fluke 23 or Megger M2006)

• Short circuit strap of 0.75mm² conductor (with yellow insulation)terminated with insulated crocodile clips at each end and approximately 25cm in length

• FS2600 Set-up Box, (WSL Part No E21476/1). See note (b)

• Pin Extraction Tool

• Universal Track Circuit Shunt Box

• Signalling Technician’s Tool Kit.

Notes:

a) It is recommended that two additional configuration plugs, complete withlinks and labels, are available so that if the configuration plug links requirealteration, time can be saved by using a new plug. The used plug can have itslinks removed at a later time.

b) If an FS2600 Set-up Box is not available, the following additional items willbe required:

• Test lead for DVM to Rx socket

• Calculator


• Double Rail Set-up Plug. This shall be made from WSL Part No.61475204 and four wire links as follows: Insert the four wire linksbetween connectors 1&9, 5&8, 4&14 and 13&15 in a blank 15-way Dtype connector. The plug shall then be labelled to show that it is a set-up plug for test use only.

10.3 TRANSMITTER TEST

10.3.1 Preparation

a) In single rail track circuits, set the variable capacitor (which was part of thesuperseded 50Hz installation) to the appropriate capacitance for the trackcircuit channel, as given in Figure 55:

Channel Capacitance (µµF) Channel Capacitance (µµF)

1 20 6 17

2 19 7 16

3 18 8 16

4 18 9 15

5 17 10 15

Figure 55

b) Check that the Tx output wires are connected to the appropriate terminalsfor the type of track circuit. (See Figure 57.)

CAUTION: When making electrical connections to the Tx, care must betaken to view the unit “straight on” as a parallax error may arise if viewed at anangle.

c) Check that the Tx is the correct channel for the location.

d) Ensure that one of the following applies at the Rx end:

• The Rx set-up plug and the Rx end track fuse and track link (single rail)are fitted

• The Rx set-up box is connected and the Rx end track fuse and track linkare fitted

• The Rx end track fuse and track link (single rail) are removed.



Note: If the third option of removing the track fuse is taken, this may resultin the Tx end rail voltages being below their minimum level. In this case, theTx end rail voltages must be rechecked after the Rx is commissioned.

e) Ensure that the Tx lineside apparatus housing or equipment building wiringdoes not run in parallel with other FS2600 track circuit cables of the sameoperating channel for more than 20m.

10.3.2 Test Procedure

a) Measure the 110V supply voltage and ensure that it is less than 121V beforefitting the BX110 fuse.

b) The Tx is supplied with the voltage adjustment set to 115V. To set theadjustment, measure the power supply voltage and refer to Figure 56 to setthe voltage tap required.

MEASURED SUPPLY(V a.c.)

VOLTAGE ADJUST TAPS

MORE THAN 121V ADJUST 110V SUPPLY

99V - 121V 115V TAP

LESS THAN 99V 105V TAP

Note: The supply voltage must be within the limits shown below or the outputwill be inhibited and the internal fuse may rupture.

NOMINAL SUPPLY(V a.c.)

VOLTAGE AT WHICHCUT-OUT OPERATES

115V 137 V

105 V 125 V

95 V 113 V

Figure 56

c) Connect the power supply to the Tx by fitting the BX110 fuse. Allow onesecond for the Tx to power-up, then ensure that the Tx 'SUPPLY' and'OUTPUT' LEDs are lit. Measure the 110V input supply at the Tx terminalblock and ensure that it is consistent with the tap setting.


d) Measure the voltage on the Tx output terminals and ensure that it is asgiven in Figure 57. Fit the Tx end track fuse and ensure that the outputvoltage is still within the limits given in Figure 57.

e) Check that the rail voltage is as given in Figure 57.

TYPE OF TRACKCIRCUIT

TX OUTPUTTERMINALS

OUTPUTVOLTAGE

(V A.C.)

RAILVOLTAGE

(V A.C.)

SINGLE RAIL 1 AND 2 14 - 24 15 - 19

DOUBLE RAILWITH NOINTERMEDIATE BOND

3 AND 4 80 - 120 5 - 11

DOUBLE RAIL WITH ANINTERMEDIATE BOND

5 AND 6 160 - 240 6 - 15

Figure 57

10.4 TRANSMITTER IMPEDANCE BOND TEST

a) Measure the voltage between the lineside apparatus housing metalwork andthe surge arrestor terminal E. If the voltage is greater than 10V, reverse thetail connections at the impedance bond (unless the cores are incorrectlyconnected with reference to the wiring diagrams).

WARNING: Ensure that the Tx end track circuit fuse is removed beforemaking any alterations or connections to the impedance bond.

b) Remove the Tx end track fuse and apply a short circuit across the tuningcapacitor in the Tx end impedance bond. Fit the Tx end track fuse andcheck that the voltage across the auxiliary coil is less than that across thecables from the Tx, (refer to Figure 50 or 51). If this is not the case,reverse the phasing of the impedance bond as follows:

• Remove the Tx end track fuse

• Interchange the positions of the rail cables and 2 core tail cable asshown in Figure 50 or 51

• Fit the Tx end track fuse and check that the voltage across the auxiliarycoil is now less than that across the cables from the Tx

• Repeat test a), above.



c) Measure the rail voltage at the Tx end. Check that the ratio of the railvoltage to the auxiliary coil voltage is approximately 1:56.

d) Remove the Tx end track fuse, remove the short circuit across the tuningcapacitor and refit the Tx end track fuse.

e) Measure the voltage across the rails at the Tx end. Check that this is nowgreater than that measured above. If it is not within the limits given inFigure 57, check that the correct tuning capacitor is fitted at the Tx end andRx end impedance bonds, and at the intermediate impedance bond (iffitted).

f) Re-check the Rx end conditions as stated in section 10.3.1(d) if the railvoltage is still low.

10.5 INTERMEDIATE IMPEDANCE BOND TEST

WARNING: Before making connections or alterations to the Rx end orintermediate impedance bond, apply a short circuit across the rails.

a) With a short circuit across the rails, temporarily apply a short circuit acrossthe tuning capacitor using the short circuit strap. Remove the short circuitfrom across the rails and check that the rail voltage has decreased.

b) Apply a short circuit across the rails and temporarily remove or disconnectone side of the tuning capacitor. Remove the short circuit from across therails and check that the rail voltage has decreased.

c) When checks are complete, ensure that all short circuits applied at the railsor the impedance bonds for testing or safety have been removed.

10.6 RECEIVE END IMPEDANCE BOND TEST

WARNING: Before making connections or alterations to the Rx end orintermediate impedance bond, apply a short circuit across the rails.

a) Apply a short circuit across the rails and remove the Rx end track fuse.Using the short circuit strap, apply a short circuit across the tuningcapacitor in the Rx end impedance bond. Remove the short circuit fromacross the rails and check that the voltage across the auxiliary coil is lessthan that across the cables to the Rx (refer to Figure 50 or 51). If this is notthe case, reverse the phasing of the impedance bond as follows:

• Apply a short circuit across the rails

• Interchange the positions of the rail leads and 2 core tail cable as shownin Figure 50 or 51


• Remove the short circuit from across the rails. Check that the voltageacross the auxiliary coil is now less than that across the cables to the Rx

b) Apply a short circuit across the rails, remove the short circuit strap fromacross the tuning capacitor and remove the short circuit from across therails. Refit the Rx end track fuse.

c) Measure the voltage between the lineside apparatus housing metalwork andthe surge arrestor terminal E. If it is greater than 10V, reverse the tail cableconnections at the impedance bond (unless the cores are incorrectlyconnected with reference to the wiring diagrams).

d) Measure and record the voltage across the rails and ensure that it is greaterthan 3V.

e) Measure the voltage across the auxiliary coil

• Check that the ratio between the rail voltage and the auxiliary coilvoltage is approximately 1:56

• Repeat test a), above.

f) When checks are complete, ensure that all short circuits applied at the railsor the impedance bonds for testing or safety have been removed.

10.7 RECEIVER SENSITIVITY SET-UP

The setting-up procedure for double rail track circuits can be carried out in oneof two ways depending on whether a FS2600 set-up box is available or not. If aset-up box is available, proceed in accordance with section 10.7.1. If a set-upbox is not available, proceed in accordance with section 10.7.2.

The setting-up procedure for single rail track circuits is given in section 10.7.3.

10.7.1 Receiver Sensitivity set-up Using set-up Box (Double Rail)

Note: During this procedure, if any of the controls or indications do notfunction in accordance with this specification, the set-up box must be assumedto be faulty and Rx set-up must be carried out with a replacement set-up boxor as detailed in section 10.7.2.

10.7.1.1 Preparation

a) Check that the Rx is the correct channel for the location.

b) Ensure that the Tx, impedance bonds and tuning capacitors correspondingto the Rx are installed and have been checked in accordance with Figure 57and 58.



c) Remove and retain the protective covers from the Rx D-type connectors.

d) Ensure that the 110V supply fuse and the fuse between the Rx and rails areboth removed.

e) Measure the 110V supply and ensure that it is between 88V and 121V a.c.

f) Fit the 110V supply fuse. Allow 5 seconds and ensure that the SUPPLY LEDindicator on the Rx is lit and the “µP - A RUNNING” and“µP - B RUNNING” LEDs are both flashing.

g) Connect the shunt box across the rails at the intermediate bond, or, if anintermediate bond is not fitted, at the Rx end of the track circuit. Ensurethat good connections are made to the rails by checking that the rail voltagedisappears when 0Ω is applied.

10.7.1.2 Set-up Procedure

CAUTION: To prevent damage to the equipment on double rail track circuits,a set-up plug or configuration plug must not be removed from the Rx if thetrack fuse is fitted.

Note: See the section on Instrumentation for details of the set-up box.

a) Prepare the set-up box as follows:

Set the DVM to V a.c. and connect it to SK1 AND SK2 on the set-up box

Set MIN/MAX control to 'MAX'.

Set both the COARSE and MEDIUM switches to position 4 and the FINE switchto position 1.

Set the LINK switch to 'SET-UP'.

Fit a blank configuration plug shell to the 15-way D-type connector on the set-up box. Ensure that the configuration plug shell mates correctly with the D-type connector as it is possible to force it on 180° out of alignment.

Connect the set-up box loom 25-way connector to the set-up box. Connectthe other ends of the loom to the 9-way and 15-way connectors on the Rx.

b) Fit the track fuse. (The track circuit may not energise at this time.)

c) Look up the Channel Specific Value for the channel number of the trackcircuit in Figure 58 for track circuits with an intermediate bond, or Figure59 for track circuits without an intermediate bond.


Figure 58 gives channel specific values for track circuits with intermediateimpedance bonds:

WITH INTERMEDIATE IMPEDANCE BOND

CHANNEL NUMBER CHANNEL SPECIFIC VALUES MPVSET-UP

STEP INCREASES

CH 1 0.957 6

CH 2 0.963 5

CH 3 0.968 3

CH 4 0.974 1

CH 5 0.978 2

CH 6 0.982 3

CH 7 0.987 4

CH 8 0.992 4

CH 9 0.995 3

CH 10 1.000 0

Figure 58

Figure 59 gives channel specific values for track circuits without intermediateimpedance bonds:

WITHOUT INTERMEDIATE IMPEDANCE BOND

CHANNEL NUMBER CHANNEL SPECIFIC VALUES MPVSET-UP

STEP INCREASES

CH 1 0.961 6

CH 2 0.967 5

CH 3 0.972 3

CH 4 0.977 1

CH 5 0.980 2

CH 6 0.984 3

CH 7 0.989 4

CH 8 0.993 4

CH 9 0.996 3

CH 10 1.000 0

Figure 59



d) Press the SET-UP button and adjust the MIN/MAX control until the voltageindicated on the DVM is the same as the Channel Specific Value. Lock theMIN/MAX control and release the SET-UP button.

e) Set the shunt box to 4.0Ω and press the shunt box button.

f) Press the set-up button and record the voltmeter reading as 'RATIO'.Release the set-up button and the shunt box button.

g) From the value of 'RATIO' recorded above, look up the Monitor PointVoltage (MPVSET-UP) on the table in Figure 60 for track circuits with anintermediate bond or Figure 61 for track circuits without an intermediatebond.

WARNING: If a track circuit with an intermediate bond is set up forratios greater than 0.73, a right side failure of the track circuit may result.

WARNING: If a track circuit without an intermediate bond is set up forratios greater than 0.64, a right side failure of the track circuit may result.

Note: The ‘BALLAST (Ω)’ column indicates the total ballast resistance forthat track circuit as deduced by the set-up procedure. To convert thisnumber into Ωkm, multiply by the track circuit length in km.


Figure 60 gives the desired set-up voltages for track circuits withintermediate impedance bonds (extends over two pages):


RATIO MPV MPV BALLAST

FROM TO MPVSET-UP UPPERLIMIT

LOWERLIMIT

(ΩΩ)

0.523 0.531 7.40 7.49 7.31 1000

0.531 0.538 7.22 7.31 7.13 800

0.538 0.545 7.04 7.13 6.95 180

0.545 0.550 6.87 6.95 6.78 77

0.550 0.556 6.70 6.78 6.62 49

0.556 0.561 6.54 6.62 6.46 36

0.561 0.566 6.38 6.46 6.30 28

0.566 0.572 6.22 6.30 6.15 23

0.572 0.577 6.07 6.15 6.00 19

0.577 0.582 5.92 6.00 5.85 17

0.582 0.587 5.78 5.85 5.71 15

0.587 0.592 5.64 5.71 5.57 13

0.592 0.597 5.50 5.57 5.43 12

0.597 0.602 5.37 5.43 5.30 11

0.602 0.607 5.23 5.30 5.17 9.8

0.607 0.612 5.11 5.17 5.04 9.0

0.612 0.616 4.98 5.04 4.92 8.3

0.616 0.621 4.86 4.92 4.80 7.7

0.621 0.626 4.74 4.80 4.68 7.2

0.626 0.630 4.63 4.68 4.57 6.7

0.630 0.635 4.51 4.57 4.46 6.3

0.635 0.640 4.40 4.46 4.35 5.9

0.640 0.644 4.30 4.35 4.24 5.6

0.644 0.648 4.19 4.24 4.14 5.3

0.648 0.653 4.09 4.14 4.04 5.0

0.653 0.657 3.99 4.04 3.94 4.8

0.657 0.661 3.89 3.94 3.84 4.5

0.661 0.666 3.80 3.84 3.75 4.3

0.666 0.670 3.70 3.75 3.66 4.1

0.670 0.674 3.61 3.66 3.57 3.9

0.674 0.678 3.53 3.57 3.48 3.8






LOWERLIMIT

(ΩΩ)

0.678 0.682 3.44 3.48 3.40 3.6

0.682 0.686 3.36 3.40 3.32 3.5

0.686 0.690 3.27 3.32 3.23 3.3

0.690 0.694 3.19 3.23 3.16 3.2

0.694 0.698 3.12 3.16 3.08 3.1

0.698 0.701 3.04 3.08 3.00 2.9

0.701 0.705 2.97 3.00 2.93 2.8

0.705 0.709 2.89 2.93 2.86 2.7

0.709 0.712 2.82 2.86 2.79 2.6

0.712 0.716 2.75 2.79 2.72 2.5

0.716 0.719 2.69 2.72 2.65 2.5

0.719 0.723 2.62 2.65 2.59 2.4

0.723 0.726 2.56 2.59 2.53 2.3

0.726 0.730 2.50 2.53 2.47 2.2

0.730 0.733 2.43 2.47 2.40 2.2

0.733 0.736 2.38 2.40 2.35 2.1

0.736 0.739 2.32 2.35 2.29 2.0

0.739 0.742 2.26 2.29 2.23 2.0

0.742 0.746 2.21 2.23 2.18 1.9

0.746 0.749 2.15 2.18 2.13 1.9

0.749 0.752 2.10 2.13 2.07 1.8

0.752 0.755 2.05 2.07 2.02 1.7

0.755 0.757 2.00 2.02 1.97 1.7

0.757 0.760 1.95 1.97 1.93 1.7

0.760 0.763 1.90 1.93 1.88 1.6

0.763 0.766 1.86 1.88 1.83 1.6

0.766 0.769 1.81 1.83 1.79 1.5

0.769 0.771 1.77 1.79 1.74 1.5

0.771 0.774 1.72 1.74 1.70 1.4

0.774 0.776 1.68 1.70 1.66 1.4

0.776 0.779 1.64 1.66 1.62 1.4

0.779 0.781 1.60 1.62 1.58 1.3

0.781 0.784 1.56 1.58 1.54 1.3





LOWERLIMIT

(ΩΩ)

0.784 0.786 1.52 1.54 1.50 1.3

0.786 0.789 1.49 1.50 1.47 1.2

Figure 60

Figure 61 gives the desired set-up voltages for track circuits withoutintermediate impedance bonds (extends over two pages):




LOWERLIMIT

(ΩΩ)

0.418 0.425 7.40 7.49 7.31 1000

0.425 0.432 7.22 7.31 7.13 800

0.432 0.438 7.04 7.13 6.95 280

0.438 0.444 6.87 6.95 6.78 120

0.444 0.449 6.70 6.78 6.62 74

0.449 0.454 6.54 6.62 6.46 54

0.454 0.460 6.38 6.46 6.30 42

0.460 0.465 6.22 6.30 6.15 34

0.465 0.470 6.07 6.15 6.00 29

0.470 0.476 5.92 6.00 5.85 25

0.476 0.481 5.78 5.85 5.71 22

0.481 0.486 5.64 5.71 5.57 19

0.486 0.491 5.50 5.57 5.43 17

0.491 0.496 5.37 5.43 5.30 16

0.496 0.501 5.23 5.30 5.17 14

0.501 0.507 5.11 5.17 5.04 13

0.507 0.512 4.98 5.04 4.92 12

0.512 0.517 4.86 4.92 4.80 11

0.517 0.522 4.74 4.80 4.68 10

0.522 0.527 4.63 4.68 4.57 9.7

0.527 0.531 4.51 4.57 4.46 9.1

0.531 0.536 4.40 4.46 4.35 8.6

0.536 0.541 4.30 4.35 4.24 8.0






LOWERLIMIT

(ΩΩ)

0.541 0.546 4.19 4.24 4.14 7.6

0.546 0.551 4.09 4.14 4.04 7.2

0.551 0.555 3.99 4.04 3.94 6.8

0.555 0.560 3.89 3.94 3.84 6.4

0.560 0.565 3.80 3.84 3.75 6.1

0.565 0.569 3.70 3.75 3.66 5.8

0.569 0.574 3.61 3.66 3.57 5.5

0.574 0.578 3.53 3.57 3.48 5.3

0.578 0.583 3.44 3.48 3.40 5.0

0.583 0.587 3.36 3.40 3.32 4.8

0.587 0.592 3.27 3.32 3.23 4.6

0.592 0.596 3.19 3.23 3.16 4.4

0.596 0.600 3.12 3.16 3.08 4.2

0.600 0.604 3.04 3.08 3.00 4.1

0.604 0.608 2.97 3.00 2.93 3.9

0.608 0.613 2.89 2.93 2.86 3.8

0.613 0.617 2.82 2.86 2.79 3.6

0.617 0.621 2.75 2.79 2.72 3.5

0.621 0.625 2.69 2.72 2.65 3.4

0.625 0.628 2.62 2.65 2.59 3.2

0.628 0.632 2.56 2.59 2.53 3.1

0.632 0.636 2.50 2.53 2.47 3.0

0.636 0.640 2.43 2.47 2.40 2.9

0.640 0.643 2.38 2.40 2.35 2.8

0.643 0.647 2.32 2.35 2.29 2.7

0.647 0.650 2.26 2.29 2.23 2.6

0.650 0.654 2.21 2.23 2.18 2.5

0.654 0.657 2.15 2.18 2.13 2.5

0.657 0.661 2.10 2.13 2.07 2.4

0.661 0.664 2.05 2.07 2.02 2.3

0.664 0.667 2.00 2.02 1.97 2.2

0.667 0.670 1.95 1.97 1.93 2.2

0.670 0.674 1.90 1.93 1.88 2.1





LOWERLIMIT

(ΩΩ)

0.674 0.677 1.86 1.88 1.83 2.0

0.677 0.680 1.81 1.83 1.79 2.0

0.680 0.683 1.77 1.79 1.74 1.9

0.683 0.686 1.72 1.74 1.70 1.9

0.686 0.689 1.68 1.70 1.66 1.8

0.689 0.691 1.64 1.66 1.62 1.8

0.691 0.694 1.60 1.62 1.58 1.7

0.694 0.697 1.56 1.58 1.54 1.7

0.697 0.700 1.52 1.54 1.50 1.6

0.700 0.702 1.49 1.50 1.47 1.6

Figure 61

h) Refer to the table in Figure 58 for track circuits with an intermediate bond,or Figure 59 for track circuits without an intermediate bond, and record theMPVSET-UP “step increase” for the track circuit channel number. Increasethe MPVSET-UP value by “stepping up” the appropriate table the number ofrows recorded.

Example: Track Circuit Channel 7 (with intermediate bond):

• Look up Channel Specific Value in Figure 58.Result: 0.987.

• Record 'RATIO' reading, e.g. 0.633 with a 4Ω shunt applied and thebutton pressed.

• Look up 0.633 in Figure 60 and record equivalent MPVSET-UP.Result: 4.51.

• Look up MPVSET-UP Step Increase in Figure 58 for Channel 7.Result: 4.

• Step up the table in Figure 58 four rows to give a target MPVSET-UP value.Result: 4.98.

i) Adjust the COARSE, MEDIUM AND FINE switches in turn until the meterreads as close as possible to the target MPVSET-UP and is within the upperand lower MPV limits as shown in Figure 60 or 61.



Note: If it is not possible to achieve the monitor point voltage, it isacceptable to commission the track circuit provided that the monitor pointvoltage achieved is below the desired level. This shall only be done inexceptional circumstances following an assessment of the track circuit andthe ballast value indicated from the value of 'RATIO' in the table in Figure 60or 61 as appropriate The purpose of the assessment is to judge thelikelihood of the ballast changing such that the signal falls below theenergisation level of the Rx. The Infrastructure Controller must beinformed immediately of any such adjustments.

j) Set the LINK switch from 'SET-UP' to 'LINK A'.

k) Note which LEDs on the set-up box are lit. Take one of the wire linksprovided with the configuration plug and connect it between the pinsindicated by the lit LEDs.

Note: If the 'NO LINK' LED is lit, proceed to item l).

Note: If the wire link is correctly connected, the lit LEDs will beextinguished. If the LEDs are not extinguished, or if other LEDs are lit,check whether the link has been connected correctly.

l) Set the LINK switch to 'LINK B' and repeat step k).

m) Set the LINK switch to 'LINK C' and repeat step k).

n) Set the LINK switch to 'LINK D' and repeat step k).

o) Set the link switch to 'LINK C', 'LINK B' and 'LINK A' in turn, ensuring thatall the LEDs around the configuration plug on the set-up box remainextinguished at all settings.

Note: The 'NO LINK' LED may be lit.

p) Remove the configuration plug from the set-up box and push the links fullyhome.

Note: To fit a wire link, push the pin and wire firmly into the connectorhole as far as it will go. To ensure that the pin is locked into the connector,pull the wire very gently. Do not use force when inserting and extractingpins.

Note: To remove a pin from the connector, use the extraction tool asdescribed in clause 10.7.3.


q) Fit the hood to the configuration plug. Write the link settings and thenomenclature of the track circuit on the labels provided and fix the labels tothe hood.

r) Remove the track fuse.

s) Remove the 15-way D-type plug from the Rx, leaving the 9-way connectorin place.

t) Fit the configuration plug to the Rx 'SET-UP' socket. Do not over-tightenthe fixing screws.

u) Fit the track fuse.

v) Ensure that the meter still indicates the MPVSET-UP.

Note: If the meter does not indicate a value within the lower and upperlimits of the desired MPVSET-UP, repeat the set-up procedure.

w) Record the target and real MPVSET-UP link settings and the weatherconditions on the track circuit maintenance record card.

x) With the shunt box still connected at the same position, set it to 0.7Ω anddepress the button. Measure and record the monitor point voltage andensure that the LED indicators are as given in the 'Status Shunted' column ofthe table in Figure 62. Release the shunt box button.

LED STATUSUNSHUNTED

STATUSSHUNTED

SUPPLY STEADY ON STEADY ON

µP - ARUNNING

FLASHING FLASHING

INPUT - AVALID

STEADY ON STEADY OFF

µP - BRUNNING

FLASHING FLASHING

INPUT - BVALID

STEADY ON STEADY OFF

OUTPUT STEADY ON STEADY OFF

Figure 62

y) Remove the 9-way D-type connector from the Rx and fit the protectivecover to the Rx connector.



CAUTION: The protective cover must be fitted to the Rx MONITORPOINT connector.

z) Measure and record the drop shunt value at the Rx end in accordance withPart M of RT/E/S/11752 and with reference to the following:

• The drop shunt for the FS2600 track circuit must be greater than 0.6Ωfor double rail

• The 'INPUT A VALID' and 'INPUT B VALID' LEDs may not necessarilyextinguish at the same level, but there must be no more than 10%difference between the MPV levels at which they do

• Observe the operation of the relays through the window of the Rx andensure that both relays drop when both 'INPUT VALID' LEDs areextinguished.

Note: If the drop shunt value is less than 0.6Ω, the track circuit set-upprocedure must be repeated. If this does not remedy the low drop shunt,the track circuit may be adjusted to increase the drop shunt. Too low adrop shunt value indicates an error in the set-up process or a fault withinthe track circuit. The drop shunt may be improved by adjusting theCOARSE, MEDIUM and FINE switches in turn to achieve a MPV less thanMPVSET-UP down to a minimum of 2.2V. The Infrastructure Controller mustbe informed immediately of any such adjustments.

WARNING: NEVER INCREASE THE GAIN.

Note: Record all remaining readings on the track circuit maintenancerecord card.

aa) Proceed as detailed in section 10.7.3: “Set-up Procedure Completion”.

10.7.2 Receiver Sensitivity set-up Without set-up Box (Double Rail)


• Check that the Rx is the correct channel for the location

• Ensure that the Tx, impedance bonds and tuning capacitors corresponding tothe Rx are installed and have been checked in accordance with sections 10.3- 10.6.

10.7.2.2 Set-up Procedure

CAUTION: To prevent damage to the equipment on double rail trackcircuits, a set-up plug or configuration plug must not be removed from the Rx ifthe track fuse is fitted.


Note: Figure 63 provides a summary of the measurements and calculationsrequired during the following procedure to determine MPVCLEAR andMPVSHUNTED:

ACTION RESULT

APPLY 4Ω SHUNT AND MEASURE MPVSHUNTED MPVSHUNTED (A)

REMOVE 4Ω SHUNT AND MEASURE MPVCLEAR MPVCLEAR (B)

DIVIDE (A) BY (B) MPVSHUNTED,MPVCLEAR

(C)

LOOK UP CHANNEL SPECIFIC VALUE IN FIGURE 57 OR 58 CHANNELSPECIFIC VALUE

(D)

MULTIPLY (C) BY (D) RATIO (E)

LOOK UP (E) IN FIGURE 59 OR 60 TO DETERMINE VALUEOF MPVSET-UP

INITIAL MPVSET-UP (F)

LOOK UP MPVSET-UP STEP INCREASE IN FIGURE 57 OR 58 STEP INCREASE (G)

DETERMINE MPVSET-UP BY STEPPING UP THE TABLE (G)ROWS IN FIGURE 57 OR 58

MPVSET-UP (H)

DIVIDE (H) BY (B) GAIN (J)

LOOK UP VALUE OF (J) IN FIGURE 64 TO DETERMINEPOSITIONS FOR SENSITIVITY SETTING LINKS

LINK SETTINGS

Figure 63

a) Ensure that the 110V supply fuse and the fuse between the Rx and rails areboth removed.

b) Remove and retain the protective covers from the Rx D-type connectors.

c) Measure the 110V supply and ensure that it is between 88V and 121Va.c.

d) Set the DVM to V a.c. and connect it to the Rx 'MONITOR POINT'connector using the test lead.

e) Connect the double rail set-up plug to the Rx 'SET UP' connector.

f) Fit the power supply fuse. Allow 5 seconds and ensure that the LEDindicators on the Rx are as given in Figure 64:



LED STATUS

SUPPLY Steady on

µP - A RUNNING Flashing

INPUT - A VALID Not relevant

µP - B RUNNING Flashing

INPUT - B VALID Not relevant

OUTPUT Not relevant

Figure 64

g) Fit the track fuse. (The track circuit may not energise at this time.)

h) Connect the shunt box across the rails at the intermediate bond, or, if anintermediate bond is not fitted, at the Rx end of the track circuit. Set theshunt box to 4.0Ω and depress the button. Measure the monitor pointvoltage and record it as MPVSHUNTED.

i) Release the button. Measure the monitor point voltage again and record itas MPVCLEAR.

The following procedure shall be used to determine MPVSET-UP and the positionof the links:

a) Using the calculator, divide MPVSHUNTED by MPVCLEAR. Multiply the result bythe Channel Specific Value derived from Figure 58 for track circuits with anintermediate bond or Figure 59 for track circuits without an intermediatebond to give the ratio. Record the ratio on the track circuit maintenancerecord card.

b) From the ratio thus obtained, look up the desired set-up voltage (MPVSET-UP)in Figure 60 for track circuits with intermediate bond or Figure 61 for trackcircuits without intermediate bond.

Note: Unless the track circuit frequency is Channel 10, the MPVSET-UP must beincreased as follows:

c) Refer to Figure 58 for track circuits with an intermediate bond or Figure 59for track circuits without an intermediate bond and record the MPVSET-UP

STEP INCREASE for the track circuit channel number. Increase theMPVSET-UP value by stepping up the table in Figure 60 or 61 as appropriatethe number of rows recorded.


d) Using the calculator, divide MPVSET-UP by MPVCLEAR to determine the gainand, from the gain obtained, determine the required positions for thesensitivity setting links from Figure 65 (extends over two pages):

MPVSET-UP

MPVCLEAR

(GAIN)

LINKS MPVSET-UP

MPVCLEAR

(GAIN)

LINKS

1.00 8 - 14 5 - 13 4 - 15 2.30 8 - 14 6 - 4 5 - 15

1.05 8 - 14 5 - 13 7 - 4 2.35 8 - 14 6 - 4 7 - 5

1.10 8 - 14 13 - 5 15 - 12 2.40 8 - 6 5 - 13 4 - 15

1.15 8 - 14 13 - 5 7 - 12 2.45 8 - 6 5 - 13 7 - 4

1.20 8 - 14 13 - 12 4 - 15 2.50 8 - 6 5 - 13 15 - 12

1.25 8 - 14 13 - 12 7 - 4 2.55 8 - 6 5 - 13 7 - 12

1.30 8 - 14 No Link 15 - 13 2.60 8 - 6 13 - 12 4 - 15

1.35 8 - 14 No Link 7 - 13 2.65 8 - 6 13 - 12 7 - 4

1.40 8 - 14 4 - 13 15 - 12 2.70 8 - 6 No Link 15 - 13

1.45 8 - 14 4 - 13 7 - 12 2.75 8 - 6 No Link 7 - 13

1.50 8 - 14 13 - 12 5 - 15 2.80 8 - 6 4 - 13 15 - 12

1.55 8 - 14 13 - 12 7 - 5 2.85 8 - 6 4 - 13 7 - 12

1.60 8 - 14 4 - 13 5 - 15 2.90 8 - 6 13 - 12 5 - 15

1.65 8 - 14 4 - 13 7 - 5 2.95 8 - 6 13 - 12 7 - 5

1.70 8 - 14 5 - 6 4 - 15 3.00 8 - 6 4 - 13 5 - 15

1.75 8 - 14 5 - 6 7 - 4 3.05 8 - 6 4 - 13 7 - 5

1.80 8 - 14 5 - 6 15 - 12 3.10 No Link 8 - 5 4 - 15

1.85 8 - 14 5 - 6 7 - 12 3.15 No Link 8 - 5 7 - 4

1.90 8 - 14 12 - 6 4 - 15 3.20 No Link 8 - 5 15 - 12

1.95 8 - 14 12 - 6 7 - 4 3.25 No Link 8 - 5 7 - 12

2.00 8 - 14 No Link 6 - 15, 3.30 No Link 12 - 8 4 - 15

2.05 8 - 14 No Link 7 - 6 3.35 No Link 12 - 8 7 - 4

2.10 8 - 14 6 - 4 15 - 12 3.40 No Link No Link 8 - 15

2.15 8 - 14 6 - 4 7 - 12 3.45 No Link No Link 8 - 7

2.20 8 - 14 6 - 12 5 - 15 3.50 No Link 8 - 4 15 - 12

2.25 8 - 14 6 - 12 7 - 5 3.55 No Link 8 - 4 7 - 12

3.60 No Link 8 - 12 5 - 15 4.75 8 - 6 14 - 12 7 - 4

3.65 No Link 8 - 12 7 - 5 4.80 8 - 6 No Link 15 - 14



3.70 No Link 8 - 4 5 - 15 4.85 8 - 6 No Link 7 - 14

3.75 No Link 8 - 4 7 - 5 4.90 8 - 6 4 - 14 15 - 12

3.80 8 - 13 6 - 5 4 - 15 4.95 8 - 6 4 - 14 7 - 12

3.85 8 - 13 6 - 5 7 - 4 5.00 8 - 6 14 - 12 5 - 15

3.90 8 - 13 6 - 5 15 - 12 5.05 8 - 6 14 - 12 7 - 5

3.95 8 - 13 6 - 5 7 - 12 5.10 8 - 6 4 - 14 5 - 15

4.00 8 - 13 6 - 12 4 - 15 5.15 8 - 6 4 - 14 7 - 5

4.05 8 - 13 6 - 12 7 - 4 5.20 8 - 13 5,14 4 - 15

4.10 8 - 13 No Link 6 - 15 5.25 8 - 13 5,14 7 - 4

4.15 8 - 13 No Link 7 - 6 5.30 8 - 13 5 - 14 15 - 12

4.20 8 - 13 6 - 4 15 - 12 5.35 8 - 13 5 - 14 7 - 12

4.25 8 - 13 6 - 4 7 - 12 5.40 8 - 13 14 - 12 4 - 15

4.30 8 - 13 6 - 12 5 - 15 5.45 8 - 13 14 - 12 7 - 4

4.35 8 - 13 6 - 12 7 - 5 5.50 8 - 13 No Link 15 - 14

4.40 8 - 13 6 - 4 5 - 15 5.55 8 - 13 No Link 7 - 14

4.45 8 - 13 6 - 4 7 - 5 5.60 8 - 13 4 - 14 15 - 12

4.50 8 - 6 5 - 14 4 - 15 5.65 8 - 13 4 - 14 7 - 12

4.55 8 - 6 5 - 14 7 - 4 5.70 8 - 13 14 - 12 5 - 15

4.60 8 - 6 5 - 14 15 - 12 5.75 8 - 13 14 - 12 7 - 5

4.65 8 - 6 5 - 14 7 - 12 5.80 8 - 13 4 - 14 5 - 15

4.70 8 - 6 14 - 12 4 - 15 5.85 8 - 13 4 - 14 7 - 5

Figure 65

Note: If it is not possible to achieve the MPVSET-UP, it is acceptable tocommission the track circuit provided that the monitor point voltageachieved is below the MPVSET-UP and above 2.2V. This shall only be done inexceptional circumstances following an assessment of the track circuit andthe ballast value indicated from the value of 'RATIO' in Figure 60 or 61. Thepurpose of the assessment is to judge the likelihood of the ballast changingsuch that the signal falls below the energisation level of the Rx. TheInfrastructure Controller must be informed immediately of any suchadjustments.

e) Proceed as detailed in clause 10.7.3: Set-up Procedure Completion.


Note: If it is necessary to deduce the gain from the link settings, refer toFigure 66.

Figure 66 gives gain link settings (extends over two pages):

LINK C LINK B LINK A GAIN LINK C LINK B LINK A GAIN

No Link No Link 8 - 15 3.40 8 - 6 13 - 12 5 - 15 2.90

No Link No Link 8 - 7 3.45 8 - 6 13 - 12 7 - 4 2.65

No Link 8 - 4 5 - 15 3.70 8 - 6 13 - 12 7 - 5 2.95

No Link 8 - 4 7 - 12 3.55 8 - 6 14 - 12 4 - 15 4.70

No Link 8 - 4 7 - 5 3.75 8 - 6 14 - 12 5 - 15 5.00

No Link 8 - 4 15 - 12 3.50 8 - 6 14 - 12 7 - 4 4.75

No Link 8 - 5 4 - 15 3.10 8 - 6 14 - 12 7 - 5 5.05

No Link 8 - 5 7 - 12 3.25 8 - 13 No Link 6 - 15 4.10

No Link 8 - 5 7 - 4 3.15 8 - 13 No Link 7 - 14 5.55

No Link 8 - 5 15 - 12 3.20 8 - 13 No Link 7 - 6 4.15

No Link 8 - 12 5 - 15 3.60 8 - 13 No Link 15 - 14 5.50

No Link 8 - 12 7 - 5 3.65 8 - 13 4 - 14 5 - 15 5.80

No Link 12 - 8 4 - 15 3.30 8 - 13 4 - 14 7 - 12 5.65

No Link 12 - 8 7 - 4 3.35 8 - 13 4 - 14 7 - 5 5.85

8 - 6 No Link 7 - 13 2.75 8 - 13 4 - 14 15 - 12 5.60

8 - 6 No Link 7 - 14 4.85 8 - 13 5 - 14 4 - 15 5.20

8 - 6 No Link 15 - 13 2.70 8 - 13 5 - 14 7 - 12 5.35

8 - 6 No Link 15 - 14 4.80 8 - 13 5 - 14 7 - 4 5.25

8 - 6 4 - 13 5 - 15 3.00 8 - 13 5 - 14 15 - 12 5.30

8 - 6 4 - 13 7 - 12 2.85 8 - 13 6 - 4 5 - 15 4.40

8 - 6 4 - 13 7 - 5 3.05 8 - 13 6 - 4 7 - 12 4.25

8 - 6 4 - 13 15 - 12 2.80 8 - 13 6 - 4 7 - 5 4.45

8 - 6 4 - 14 5 - 15 5.10 8 - 13 6 - 4 15 - 12 4.20

8 - 6 4 - 14 7 - 12 4.95 8 - 13 6 - 5 4 - 15 3.80

8 - 6 4 - 14 7 - 5 5.15 8 - 13 6 - 5 7 - 12 3.95

8 - 6 4 - 14 15 - 12 4.90 8 - 13 6 - 5 7 - 4 3.85

8 - 6 5 - 13 4 - 15 2.40 8 - 13 6 - 5 15 - 12 3.90

8 - 6 5 - 13 7 - 12 2.55 8 - 13 6 - 12 4 - 15 4.00

8 - 6 5 - 13 7 - 4 2.45 8 - 13 6 - 12 5 - 15 4.30



LINK C LINK B LINK A GAIN LINK C LINK B LINK A GAIN

8 - 6 5 - 13 15 - 12 2.50 8 - 13 6 - 12 7 - 4 4.05

8 - 6 5 - 14 4 - 15 4.50 8 - 13 6 - 12 7 - 5 4.35

8 - 6 5 - 14 7 - 12 4.65 8 - 13 14 - 12 4 - 15 5.40

8 - 6 5 - 14 7 - 4 4.55 8 - 13 14 - 12 5 - 15 5.70

8 - 6 5 - 14 15 - 12 4.60 8 - 13 14 - 12 7 - 4 5.45

8 - 6 13 - 12 4 - 15 2.60 8 - 13 14 - 12 7 - 5 5.75

8 - 14 No Link 6 - 15 - 2.00 8 - 14 6 - 4 5 - 15 2.30

8 - 14 No Link 7 - 13 1.35 8 - 14 6 - 4 7 - 12 2.15

8 - 14 No Link 7 - 6 2.05 8 - 14 6 - 4 7 - 5 2.35

8 - 14 No Link 15 - 13 1.30 8 - 14 6 - 4 15 - 12 2.10

8 - 14 4 - 13 5 - 15 1.60 8 - 14 6 - 12 5 - 15 2.20

8 - 14 4 - 13 7 - 12 1.45 8 - 14 6 - 12 7 - 5 2.25

8 - 14 4 - 13 7 - 5 1.65 8 - 14 12 - 6 4 - 15 1.90

8 - 14 4 - 13 15 - 12 1.40 8 - 14 12 - 6 7 - 4 1.95

8 - 14 5 - 13 4 - 15 1.00 8 - 14 13 - 5 7 - 12 1.15

8 - 14 5 - 13 7 - 4 1.05 8 - 14 13 - 5 15 - 12 1.10

8 - 14 5 - 6 4 - 15 1.70 8 - 14 13 - 12 4 - 15 1.20

8 - 14 5 - 6 7 - 12 1.85 8 - 14 13 - 12 5 - 15 1.50

8 - 14 5 - 6 7 - 4 1.75 8 - 14 13 - 12 7 - 4 1.25

8 - 14 5 - 6 15 - 12 1.80 8 - 14 13 - 12 7 - 5 1.55

Figure 66

10.7.3. Set-up Procedure Completion

a) Remove the track fuse.

b) Remove the set-up plug from the Rx. In the configuration plug providedwith the Rx, connect a wire link between pins 1 and 9 (to set the Rx for adouble rail track circuit). Connect one, two or three links as determinedfrom Figure 65 to set the sensitivity. (See Figure 67.)

Note: To fit a wire link, push the pin and wire firmly into the connectorhole as far as it will go. Pull the wire very gently to ensure that the pin islocked into the connector.

Figure 67 shows the rear view of the configuration plug.


Figure 67

Note: Ignore any numbers which appear in either of the positions markedwith an asterisk (∗).

CAUTION: Do not use force when inserting and extracting pins.

Note: To remove a pin from the connector use the extraction tool asfollows:

• Hold the connector and insert the tool as shown in Figure 68:

Figure 68

• Ensure the tool is fully inserted, i.e. approximately half of the straightsection is visible.

• Hold the wire against the tool body and extract the wire, pin and tool inone smooth action.

c) Fit the hood to the configuration plug. Write the link settings and thenomenclature of track circuit on the labels provided and affix them to thehood. Do not over-tighten the fixing screws.

d) Fit the configuration plug to the Rx 'SET UP' socket.

e) Fit the track fuse.



f) Ensure that the LED indicators on the Rx are as given in Figure 62'Status Unshunted' column.

g) Measure and record the monitor point voltage and ensure that it is thesame as MPVSET-UP already determined within the upper and lower limits asgiven in Figure 60 or 61.

Note: If the monitor point voltage is not within the lower and upper limitsof the desired MPVSET-UP, repeat the set-up procedure.

h) With the shunt box still connected at the same position, set it to 0.7Ω anddepress the button. Measure and record the monitor point voltage andensure that the LED indicators on the Rx are as given in Figure 62 'StatusShunted' column.

i) Disconnect the DVM from the 'MONITOR POINT' socket on the Rx and fitthe retained protective cover to the Rx socket.


j) Measure and record the drop shunt value at the Rx end in accordance withPart M of RT/E/S/11752, and with reference to the following:

• The drop shunt for FS2600 double rail track circuits should exceed 0.6Ω

• The 'INPUT A VALID' and 'INPUT B VALID' LEDs may not necessarilyextinguish at the same level, but there must be no more than 10%difference between the MPV levels at which they do


Note: The drop shunt value should be greater than 0.6Ω. If it is less than0.6Ω the track circuit set-up procedure must be repeated. If this does notremedy the low drop shunt value, the track circuit may be adjusted toincrease it. Too low a drop shunt value indicates an error in the set-upprocess or a fault within the track circuit. The drop shunt value may beimproved by reducing the gain setting of the Rx to achieve an MPV less thanMPVSET-UP, down to a minimum of 2.2V. The Infrastructure Controller mustbe informed immediately of any such adjustments.

WARNING: Never increase the gain.

Note: Record all remaining readings on the track circuit maintenancerecord card.


k) Proceed as detailed in section 10.8, IRJ Shorting Tests.

10.7.4 Single Rail Track Circuits


a) Check that the Rx is the correct channel for the location.

b) Ensure that the Tx corresponding to the Rx is installed and has beenchecked in accordance with clause 10.3: Transmitter Tests.

10.7.4.2 Single Rail Track Circuits: set-up Procedure

a) Remove and retain the protective covers from Rx D-type connectors.

b) Ensure that the 110V supply fuse and the fuse between the Rx and the railsare both removed.

c) Measure the 110V supply and ensure that it is between 88V and 121Va.c.

d) Connect the DVM to the Rx 'MONITOR POINT' connector using test lead.

CAUTION: During the next operation, tighten the fixing screws finger-tight only.

e) Fit the single rail configuration plug to the Rx 'SET-UP' socket.

f) Fit the power supply fuse. Allow 5 seconds and ensure that the LEDindicators on the Rx are as given in the table in Figure 62, 'Status Unshunted'column.

g) Fit the track fuse.

h) Connect the shunt box across the rails at the Rx end of the track circuit,set it to 0.7Ω and depress the button. Measure and record the monitorpoint voltage and ensure that the LED indicators on the Rx are as given inthe table in Figure 62, 'Status Shunted' column.

i) Disconnect the DVM from the 'MONITOR POINT' socket on the Rx. Fitthe retained protective cover to the Rx socket.


j) Measure and record the drop shunt value at the Rx end in accordance withPart M of RT/E/S/11752 and with reference to the following:

• The drop shunt for FS2600 single rail track circuits should exceed 1.0Ω.



• The 'INPUT A VALID' and 'INPUT B VALID' LEDs may not necessarilyextinguish at the same level, but there must be no more than 10%difference between the MPV levels at which they do.


Note: The drop shunt value should be greater than 1.0Ω. If it is less than0.6Ω, the track circuit set-up procedure must be repeated. If this does notremedy the low drop shunt value, the track circuit may be adjusted toincrease it. Too low a drop shunt value indicates an error in the set-upprocess or a fault within the track circuit. The drop shunt value may beimproved by reducing the gain setting of the Rx to achieve a MPV less thanMPVSET-UP, down to a minimum of 2.2V. The Infrastructure Controller mustbe informed immediately of any such adjustments.

WARNING: NEVER INCREASE THE GAIN.

k) Proceed as detailed in section 10.8: IRJ Shorting Tests.

10.8 IRJ SHORTING TESTS

Carry out the following tests for IRJ failure:

10.8.1 IRJ Failure at Double Rail to Double Rail Abutment

Refer to Figure 69.

Figure 69


10.8.1.1 Detection Pairs

Refer to Figure 8 and carry out the test shown in Figure 70:

ABUTMENT ACTION

Tx : Tx Refer to Figure 69: Short circuit

Tx : Rx each IRJ one at a time; at least one

Rx : Rx track relay must show occupied.

Figure 70

10.8.1.2 Non-Detection Pairs (undertaken for completeness only)

Refer to Figure 8 and carry out the test shown in Figure 71:

ABUTMENT ACTION


Tx : Rx each IRJ one at a time; one or both

Rx : Rx track relays may show occupied.

Figure 71

10.8.2 IRJ Failure at Double Rail to Single Rail Abutment

Refer to Figure 72:

Figure 72

Carry out the test shown in Figure 73:

ABUTMENT ACTION


Tx : Rx IRJ ‘X’ and track relay ‘A’ will show

Rx : Tx occupied. Short circuit IRJ ‘Y’ and

Rx : Rx track relay ‘B’ will show occupied.

Figure 73



10.8.3 IRJ Failure at Single Rail to Single Rail Abutment

The shorting test for single rail to single rail abutments will be provided whenthe use of single rail FS2600 track circuits is approved.

10.9 LIMIT TEST

The minimum drop shunt should be applied to all extremities of the trackcircuit in accordance with Part M of RT/E/S/11752 (0.6Ω for a double rail trackcircuit, 1.0Ω for a single rail track circuit).

10.10 INTERFERENCE TESTS

a) With all other track circuits within the area operating normally, remove theTx end track fuse and check that the corresponding Rx drops.

b) Measure the Rx monitor point voltage. This must be less than 0.2V.

c) Refit the Tx end track fuse.

d) Apply a short circuit across the rails at the Tx.

e) Measure the Rx monitor point voltage. This must be less than 0.2V.

Note: If the cross-talk measurements exceed 0.2V, determine the source byde-energising or shunting other FS2600 track circuits in the area. If the sourceis the same channel, then the track circuit must NOT be commissioned. If thesource is NOT the same channel then the track circuit may be commissioned ifthe measurements do not exceed 0.5V, but the cause must be established.


11 SPECIAL MAINTENANCE PROCEDURES

11.1 INTRODUCTION

These Procedures describe the requirements for maintenance of FS2600 trackcircuit equipment. Refer also to Signalling Maintenance Specification TC26.General maintenance of track circuits shall be carried out in accordance withPart M of RT/E/S/11752.


Track circuit maintenance consists of:

• Routine Examination

• Drop Shunt Test

• Full Test

• Corrective Maintenance.

Note: Results of tests and details of track conditions (weather, ballast, etc.)shall be recorded on the track circuit maintenance record card for futurereference.

11.2 ROUTINE EXAMINATION

11.2.1 General

In addition to the routine examination procedures given in RT/E/S/11752, amonitor point voltage check shall be carried out and the results recorded.

11.2.2 Monitor Point Voltage Check

11.2.2.1 Test Equipment Required

• Digital Voltmeter (DVM), Fluke 23 or Megger M2006

• Test lead for DVM to Rx socket

• Universal Track Circuit Shunt Box.



11.2.2.2 Test Procedure

a) Remove and retain the protective cover from the Rx 'MONITOR POINT'socket.

b) Connect the DVM to the 'MONITOR POINT' socket on the Rx using thetest lead.

c) Ensure that the LED indicators on the Rx are as given in Figure 74 for trackcircuit clear condition. Measure and record the monitor point voltage.

d) Connect the shunt box across the rails at the intermediate impedance bond,if fitted, or at the Rx end of the track circuit. Set the shunt box to 0.7Ω(for double rail or single rail) and depress the button. Ensure that the LEDindicators on the Rx are as given in Figure 74 for track shunted condition.Measure and record the monitor point voltage. Release the button.

LED STATUSTRACK CLEAR

STATUSTRACK SHUNTED

SUPPLY Steady on Steady on

µP - A RUNNING Flashing Flashing

INPUT - A VALID Steady on Steady off

µP - B RUNNING Flashing Flashing

INPUT - B VALID Steady on Steady off

OUTPUT Steady on Steady off

Figure 74

e) Disconnect the DVM from the 'MONITOR POINT' socket on the Rx and fitthe retained protective cover to the socket. Disconnect the shunt boxfrom the rails.

CAUTION: The protective cover must be fitted to the 9-way Rxconnector.

f) The monitor point voltage readings shall be compared with previousrecords obtained under comparable conditions. If the results are notsimilar, the cause should be investigated and rectified as appropriate. A fulltest shall then be carried out. Refer to section 11.4, Full Test.

11.3 DROP SHUNT TEST

The general procedure for carrying out a drop shunt test is given in Part M ofRT/E/S/11752. When carrying out a drop shunt test of the FS2600 track circuit,observe the following:


a) The minimum drop shunt for the FS2600 track circuit should exceed 0.6Ω fordouble rail or 1.0Ω for single rail track circuits.

b) The 'INPUT A VALID' and 'INPUT B VALID' LEDs may not extinguish at thesame monitor point voltage reading. However, the higher reading must notexceed the lower reading by more than 10%.

c) Observe the operation of the relays through the window of the Rx andensure that both relays drop when both 'INPUT VALID' LEDs areextinguished.

d) The value of the drop shunt shall be recorded.

Note: This test must be carried out at least once every 18 months to ensurethe correct operation of the track circuit.

11.4 FULL TEST

The general procedure for carrying out a full test is given in Part M ofRT/E/S/11752. The tests required at the Tx and Rx end of the FS2600 trackcircuit are given below:

11.4.1 Transmitter Tests

11.4.1.1 Test Equipment Required

Digital Voltmeter (DVM), Fluke 23 or Megger M2006.

11.4.1.2 Test Procedure

Measure the voltage output on the Tx output terminals and the voltage acrossthe rails at the Tx end. Ensure that the voltages are within the limits given inFigure 75.



TYPE OF TRACK CIRCUIT TX OUTPUTTERMINAL

OUTPUTVOLTAGE

(V a.c.)

RAIL VOLTAGE

(V a.c.)

SINGLE RAIL TRACK CIRCUIT 1 AND 2 14 - 24 15 - 19

DOUBLE RAIL TRACKCIRCUITWITH NO INTERMEDIATEBOND

3 AND 4 80 - 120 5 - 11

DOUBLE RAIL TRACKCIRCUIT WITH ANINTERMEDIATE BOND

5 AND 6 160 - 240 6 - 15

Figure 75

11.4.2 Receiver Tests

Carry out a full Rx sensitivity set-up procedure as detailed in section 10.7.

11.5 CORRECTIVE MAINTENANCE

11.5.1 Maintenance Philosophy

If an FS2600 unit is diagnosed as faulty, the corrective maintenance procedure isto remove the unit and replace it with a known serviceable spare. The trackcircuit affected must then be given a full test as detailed in clause 11.4 and PartM of RT/E/S/11752 before being returned to service.

Unserviceable items of equipment must be clearly labelled with the identity ofthe unit and despatched to the next level of maintenance for servicing and/orrepair together with a full description of the fault.

Refer to the following procedures for removing and replacing main units:

11.5.2 Transmitter Replacement

11.5.2.1 Tools and Equipment Required


• Maintenance copies of the site wiring diagrams


• Fuse Extractor

• Signalling Technician's Tool Kit.


11.5.2.2 Transmitter Removal

a) Remove and retain the Tx power supply fuse and the track fuse using thefuse extractor.

b) Ensure that the wires to the Tx are all clearly labelled to facilitatereconnection. Disconnect all wires from the Tx terminal block except theshort voltage adjustment link.

c) If the Tx is mounted on a wooden backboard via a mounting bracket, slidethe Tx upwards to release it from the bracket.

d) If the Tx is mounted on equipment racking, remove and retain the fourscrews, spring washers and plain washers which secure it to the racking.

11.5.2.3 Transmitter Fitting

a) Ensure that the Tx is the correct channel for the location.

b) Check that the sealing plugs are intact and undamaged.

Note: The plugs are fitted in the top and bottom of the front and rearfaces of the Tx. The plugs on the front face are behind blanking plates asshown in Figure 32.

c) If the Tx is to be mounted on a wooden backboard via a mounting bracket,fit the four shouldered screws into the rear of the Tx. Ensure that theblanking plates are fitted over the unused holes in the front of the Tx and fitthe Tx to the mounting bracket by sliding the screw heads down the slotson the bracket. (See section 9, Installation Procedures.)

CAUTION: To prevent damage to the Tx, use only the M5 x 10mmscrews provided with the unit. Under no circumstances must longer screwsbe used.

d) If the Tx is to be mounted on equipment racking, it may be mounted viatapped holes in either the front or rear face depending on whether the unitis to be front or rear mounted. Fit the blanking plates over the unusedholes. Fit the Tx in the appropriate position and secure in place with thefour M5 10 mm screws, fitting a flat washer and spring washer onto eachscrew (refer to Figure 45).

e) Connect the wires to the terminal block on the front of the Tx.

f) Carry out the Tx test and the Rx sensitivity set-up procedure given in section10.7.



11.5.3 Receiver Replacement

11.5.3.1 Tools and Equipment Required




• Fuse Extractor

• Rx Release Tool

• Signalling Technician's Tool Kit.

11.5.3.2 Receiver Removal

a) Remove the Rx power supply fuse and the track fuse using the fuseextractor.

b) Pull the Rx support handle forward from the stowed position and hold itwith one hand to prevent the unit falling forward when the lock plunger isreleased.

c) Lift the lock plunger to disengage the lock and allow the Rx to move slightlyforward just enough to prevent the lock plunger re-engaging. (See Figure46.) If access is restricted, the lock plunger release tool may be required.

d) Still holding the handle with one hand, support the Rx with the other handand withdraw it from the plugboard by pulling it forwards.

Note: Do not remove the configuration plug from the 'set-up' socket on thefront of the Rx for double rail track circuits. This is to ensure that the existingconfiguration plug is not fitted to the new Rx which must have a sensitivityset-up carried out. All Rxs are set to the same sensitivity on single rail trackcircuits.

11.5.3.3 Receiver Fitting

a) Ensure that the Rx power supply fuse and the track fuse are both removed.

b) Ensure that the Rx is the correct frequency for the location. Check that itssealing plugs, which are fitted to detect unauthorised access are intact andundamaged.

Note: The plugs are fitted on the rear of the Rx to protect the screws thatsecure the handle. (See Figure 48.)


c) Support the base of the Rx with one hand and grasp the handle with theother hand. Push the Rx straight back onto its plugboard and ensure thatthe lock plunger engages.

d) Push the sliding handle back to the stowed position.

Note: Do not fit the configuration plug from the original Rx for double railtrack circuits. It is essential to carry out the full set-up procedure on thenew Rx. For single rail track circuits, a standard configuration plug is fitted.

e) Carry out the Rx sensitivity set-up procedure given in section 10.7.



12 SPECIAL FAULT FINDING PROCEDURES

12.1 INTRODUCTION

This section describes the fault finding procedures for FS2600 track circuitequipment. General fault finding for track circuits shall be carried out inaccordance with Part P of RT/E/S/11752.


WARNING: Under no circumstances may an FS2600 double rail track circuitbe operated in temporary single rail mode.

12.2 FAULT FINDING PROCEDURES

The state of the LEDs on the Transmitter (Tx) and Receiver (Rx) provide anindication of the condition of the units. Figures 76 and 77 illustrate the purposeof each LED. If the track circuit indicates occupied when no train is present,follow the fault charts in Figures 76 to 79 to identify the location of the fault.

12.3 CAPACITOR TESTING

Note: The capacitor may be effectively checked by substitution.

WARNING: Short circuit the capacitor connections to discharge it beforeand after megger testing.

If a capacitor is suspected of being short-circuit, it can be checked by removingit from the impedance bond and testing it with a Megger. After an initialdeflection, the Megger should give a steady reading of more than 1MΩ. If thereis no initial deflection, the capacitor may be open circuit.

12.4 TRANSMITTER LED INDICATIONS

The two LEDs on the front of the Tx provide indications as shown in Figure 76.

STATE OF LED

SUPPLY OUTPUT CONDITION OF UNIT

ON ON INPUT POWER IS ON AND AN OUTPUT IS PRESENT

ON OFF TX INTERNAL FAULT

OFF OFF POWER SUPPLY TO TX FAILED

Figure 76


12.5 RECEIVER LED INDICATIONS

Figure 77 gives the LED indications for a track circuit in both clear and occupiedconditions. Any other combination indicates a faulty unit.

LED TRACK CIRCUITCLEAR

TRACK CIRCUITOCCUPIED

SUPPLY STEADY ON STEADY ON

µP-A RUNNING FLASHING FLASHING

INPUT - A VALID STEADY ON STEADY OFF

µP-B RUNNING FLASHING FLASHING

INPUT - B VALID STEADY ON STEADY OFF

OUTPUT STEADY ON STEADY OFF

Figure 77

Note 1: 'µP-A RUNNING' and 'µP-B RUNNING' LEDs should always beflashing (not necessarily synchronously) otherwise there is an internal Rx fault.

Note 2: 'INPUT - A VALID' and 'INPUT - B VALID' LEDs should generally bein the same state. However, since the two processors do not runsynchronously, these two LEDs may not change states simultaneously when thetrack circuit occupancy changes, and a momentary delay may be observed.

12.6 IMPEDANCE BOND CHECK

Note: Reference shall be made to RT/E/PS/1002.

12.6.1 Tx End Impedance Bond

Proceed as follows to check a suspect Tx end impedance bond:

WARNING: Remove the Tx end track fuse before making any alterations orconnections at the impedance bond.

a) Remove the Tx end track fuse and apply a short circuit across the tuningcapacitor in the Tx end impedance bond. Fit the Tx end track fuse.

b) Check that the voltage across the auxiliary coil is less than that across thecables from the Tx. (Refer to Figure 50 or 51.) If this is not the case,reverse the phasing of the impedance bond as described in section 10,Testing Procedures.

c) Measure the rail voltage at the Tx end.



d) Remove the Tx end track fuse, remove the short circuit across the tuningcapacitor and refit the Tx end track fuse.

e) Measure the rail voltage at the Tx end again. Check that this is now greaterthan in item b) above. If it is not within the limits given in Figure 75, checkthe tuning capacitor fitted at the Tx end and Rx end impedance bonds, andat the intermediate impedance bond (if fitted).

12.6.2 Intermediate and Rx End Impedance Bond

WARNING: Before making connections to, or alterations at, the impedancebond, apply a short circuit across the rails.

12.6.2.1 Rx End Impedance Bond Phase Test

a) Remove the Rx end track fuse and apply a short circuit across the rails.

b) Using a short circuit strap, apply a short circuit across the tuning capacitorin the Rx end impedance bond.

c) Remove the short circuit across the rails and check that the voltage acrossthe auxiliary coil is less than that across the cables to the Rx. (Refer toFigure 50 or 51.) If this is not the case, reverse the phasing of theimpedance bond as described in section 10, Testing Procedures.

12.6.2.2 Intermediate and Rx End Impedance Bond Test

a) Measure the voltage across the rails and ensure that a voltage greater than3V is present.

b) Measure the voltage across the auxiliary coil. Check that the ratio betweenthe rail voltage and the auxiliary coil voltage is approximately 1:56. If it isnot, the impedance bond may be faulty.

c) If the ratio is correct, temporarily apply a short circuit across the tuningcapacitor and check that the rail voltage decreases.

12.6.2.3 Additional Test for Intermediate Impedance Bonds

Temporarily remove, or disconnect one side of the tuning capacitor and checkthat the rail voltage decreases.

12.6.2.4 Completion

When checks are complete, ensure that all short circuits applied for testing orsafety have been removed.


12.7 FAULT CHARTS

Figure 78 represents a fault chart for the Rx end of a double rail track circuit:

CHECK LIKELY FAULT ACTIONIs Rx 'SUPPLY'LED lit?

NO→ Power supply to Rx failed → Check supply voltage

YES↓

'mP RUNNING' LEDsflashing?

NO→Rx is locked up

→ Remove Rx supply fuse,wait 5 seconds, replace Rxsupply fuse, wait 5seconds, repeat check:

YES ↓OR If result of check is still'NO', change Rx (seeMaintenance Procedures)

↓Rx is Faulty → Change Rx (see

Maintenance Procedures)

Are both Rx 'INPUT VALID' LEDsOff?

NO→ If only one is lit, the Rx isfaulty

→ Change Rx (seeMaintenance Procedures)

YES ↓OR↓ If both are lit, but the

'OUTPUT' LED is Off, theRx is faulty


↓ORRx contact connectionsare suspect

→ Check Rx contactconnections

Is Monitor Point voltageless than 2V* ?

NO→ Rx is Faulty → Change Rx (seeMaintenance Procedures)

YES↓Is input voltage to surgearrestor less than 4V* ?

NO→ Fault lies between surgearrestor and Rx

→ Check surge arrestor andtrack fuse

YES↓Is a.c. rail voltage at Rxendless than 2V* ?

NO→ Fault lies between railsand surge arrestor

→ Trace voltage from rails tosurge arrestor, checkimpedance bond andcapacitor as described inthese Procedures

YES↓Check Tx in accordancewith Figure 80

* These voltages are absolute minima, generally thevoltage should be higher.

Figure 78



Figure 79 represents a fault chart for the Rx end of a single rail track circuit:

CHECK LIKELY FAULT ACTIONIs Rx 'SUPPLY'LED lit?

NO→

Power supply to Rx failed → Check supply voltage

YES↓Are both Rx 'mP RUNNING' LEDsflashing?

NO→

Rx is locked up → Remove Rx supply fuse,wait 5 seconds, replace Rxsupply fuse, wait 5seconds, repeat check:

YES ↓OR If result of check is still'NO', change Rx (seeMaintenance Procedures)

↓Rx is Faulty → Change Rx (see

Maintenance Procedures)

Are both Rx 'INPUT VALID' LEDsOff?

NO→

If only one is lit, the Rx isfaulty


YES ↓OR↓ If both are lit, but the

'OUTPUT' LED is Off, theRx is faulty


↓ORRx contact connectionsare suspect

→ Check Rx contactconnections

Is Monitor Point voltageless than 2V*?

NO→

Faulty Rx → Change Rx (seeMaintenance Procedures)

YES↓Is input voltage at trackfuse less than 2V*?

NO→

Fault lies between trackfuse and Rx

→ Check track fuse andcables

YES↓Is a.c. rail voltage at Rxendless than 2V*?

NO→

Fault lies between railsand track fuse

→ Trace voltage from rails totrack fuse

YES↓Check Tx in accordancewith Figure 81

* These voltages are absolute minima, generally thevoltage should be higher

Figure 79


Figure 80 represents a fault chart for the Tx end of a double rail track circuit:

CHECK LIKELY FAULT ACTIONIs Tx 'SUPPLY'LED lit?

NO→

Power supply to Tx failed → Check power supply

YES↓Is Tx 'OUTPUT'LED lit?

NO→

Power supply to Tx toohigh causing Tx over-voltage cut-out to operate

→ Check Tx voltageadjustment(see Testing Procedures)

YES ↓OR↓ Tx is faulty → Disconnect Tx output and

re-check:↓OR If 'OUTPUT' LED still not

lit, change Tx (seeMaintenance Procedures)

Output is short circuited (e.g. cable fault)

→ If 'OUTPUT' LED now lit,short circuited output isindicated, refer toRT/E/S/11752 forprocedures to locate ashort circuit.

Is Tx output voltage atcorrect level? (See Figure75)

NO→

Tx is Faulty → Change Tx (seeMaintenance Procedures)

YES↓Is voltage across rails at Txend at correct level?(See Figure 75)

NO→

Fault lies between Tx andrails

→ Trace voltage from Tx torails, check impedancebond and capacitor asdescribed in theseProcedures

YES↓Refer to RT/E/S/11752 forprocedures to locate adisconnection

Figure 80



Figure 81 represents a fault chart for the Tx end of a single rail track circuit:

0 LIKELY FAULT ACTIONIs Tx 'SUPPLY'LED lit?

NO→→

Power supply to Tx failed →→ Check power supply

YES↓↓Is Tx 'OUTPUT'LED lit?

NO→→

Power supply to Tx toohigh causing Tx over-voltage cut-out to operate

→→ Check Tx voltageadjustment(see Testing Procedures)

YES ↓↓OR↓↓ Tx is faulty →→ Disconnect Tx output and

re-check:↓↓OR If 'OUTPUT' LED still not

lit, change Tx (seeMaintenance Procedures)

Output is short circuited (e.g. cable fault)

→→ If 'OUTPUT' LED now lit,short circuited output isindicated, refer toRT/E/S/11752 forprocedures to locate ashort circuit.

Is Tx output voltage atcorrect level? (See Figure75)

NO→→

Tx is Faulty →→ Change Tx (seeMaintenance Procedures)

YES↓↓Is voltage across rails at Txend at correct level?(See Figure 75)

NO→→

Fault lies between Tx andrails

→→ Trace voltage from Tx torails,

YES↓↓Refer to RT/E/S/11752 forprocedures to locate adisconnection

Figure 81


13 REFERENCES

Railtrack Line Standards

RT/E/C/11004 Symbols for Plans and Sketches Used in Signalling Applications(supersedes GK/RT0004)

RT/E/C/11552 Signalling Maintenance Specifications Contents(to be superseded by RT/E/S/10660)

RT/E/C/11600 Signalling and Operational Telecommunications Design:Technical Guidance (supersedes GK/GN0600)

RT/E/C/11701 Signalling Design: Production Guidance(supersedes GK/RC0701)

RT/E/G/11710 Signalling Design Handbook (supersedes GK/RH0710)

RT/E/G/11720 Signalling Installation Handbook (supersedes GS/IH0001)

RT/E/S/11752 Train Detection (supersedes GK/RC0752, etc.)

RT/E/PS/00005 Railway Signalling Cable(supersedes GS/ES0872)

RT/E/PS/1002 Impedance Bonds

Signalling Maintenance Specifications (see RT/E/C/11552)

TC26 Westinghouse Signals FS2600 Track Circuit

Specifications

BR933 Miniature Tractive Armature A.C. Immune D.C. Slow Pick-upNeutral Line Plug-In Type for Railway Signalling Purposes

BR960 Miniature Twin Tractive Armature D.C. Neutral Line Relay Unit,Plug-In Type, for Railway Signalling Purposes

BR967 Railway Signalling Apparatus: Environmental Conditions

National/International Standards

BS 88 Cartridge fuses for voltages up to and including 1000V a.c. and1500V d.c.



BS 7671 Requirements for Electrical Installations (IEE Wiring Regulations)


14 GLOSSARY

The terms used throughout this Product Specification are defined inRT/E/S/11752.



APPENDIX A LIST OF COMPONENTS

The following is a list of all equipment required and the main components whichcomprise the FS2600 track circuit system. Westinghouse Signals (WSL) partnumbers are given where applicable:

A.1 TRANSMITTER

Description

Channel 1. WSL part No. E21413/1











A.2 RECEIVER

Description











A.3 CAPACITOR FOR S2, S2A AND WH3 (WSL) IMPEDANCEBONDS

Description

Channel 1. WSL part No. B48271/1












A.4 CAPACITOR FOR TYPE 3 (HOWELLS) IMPEDANCE BONDS

Description











A.5 ADDITIONAL COMPONENTS

Description

Rx base conversion kit WSL part no. J22762/1

Rx single rail configuration plug WSL part no. B48273/1

Pin insertion/extraction tool

Rx blank configuration plug WSL part no. 61475204

Rx DVM set-up meter lead WSL part no. B48272/1

Rx release tool WSL part no. B48259/1

Tx mounting assembly WSL part no. J22763/1

Rx base (with labels and plastic inserts) WSL part no.A59785/111

Rx base blanking plug removal tool WSL part no. J22768/1

Fuse extractor tool

Receiver sensitivity set-up box WSL part no. E21476/1


Note: WSL part no. J22762/1 comprises: 10 large self-adhesive labels, 10 smallself-adhesive labels (one for each channel), 1 round blanking plug, 20 rectangularblanking plugs and 2 pre-packed spirit wipes. WSL part no. A59785/111includes a plugboard as well as the kit described above.

A.6 OTHER EQUIPMENT AND TOOLS

For general equipment items and tools, refer to RT/E/S/11752.

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