what is axle counter.docx

8/10/2019 What is Axle counter.docx

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INDEX

Contents Page No.

INTRODUCTION 1

CLASSIFICATION OF DIGITAL AXLE COUNTER 1 Single Section Digital Axle Counter 2

Types of Axle Counter 8 Single Section Digital Axle Counter (G36) 8 Multi Section Digital Axle Counter 9 Single Section Digital Axle Counter (G36R) 10

Single Section Digital Axle Counter (G39) 12WHAT IS AXLE COUNTER 14

Applications 15 Railway Crossings 15

Advantages 15 Disadvantages 16 Installation 17

Reset and restoration 18 History 19

PERFORMANCE OF NEW TECHNOLOGIES 19

CONCLUSION 21

REFERENCE 22


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INTRODUCTION

Axle counter is a device for monitoring a specified section of track for the presence of

vehicle. Conventional axle counters were designed with transistorized circuits and ICs. Now

Axle Counters are designed using Micro-Controllers and Software program, and these arecalled as Digital Axle Counters. The communication used in the system is by means of

packets for exchange of information between units. This communication is in duplex mode

and is fail safe. (In duplex mode data is exchanged between two connected devices in both

directions simultaneously. Data flow takes place independently in both directions).

G36 is a fail-safe 2/2 microcontroller based axle counting system for section proving in

Railways. G36 can be configured to various versions using fool-proof method thus prevents

wrong configuration at site, ensures highest degree of safety. Operating mode like preparatory, clear and occupied, configuration status, wheel counts and error messages are

constantly displayed on the system LCD status panel and interactive Reset box. Magnetic

sensors detects the axle counts and direction of train movements that is transmitted to the

other end of the system to verify and clear the block. Wheel sensed at one DP will cleared at

any DP. The section status can be fed directly to further controlling systems through vital

relay contacts. Each section has two or three detection points based on configurations.

System unit is housed near the track with its DP placed at a variable distance of 15 Mts.

Reliable communication between systems with a cable loss of 30dB using V.23 FSK modem

at 1200bps, assured by CRC check with redundant messages. Fixed pair communication

along with interlocked addressing between units ensures fail-safety. Built-in event logger logs

normal and error data that can be downloaded on to a PC using RS232 serial port. Additional

FSK modem available in event logger card connected to interactive Rest Box at station

(requires extra pair in quad cable). User-friendly GUI aids to print reports.

G36 works on 24 VDC power supply, integrated with lightening surge protectors.

Stable operation at adverse environmental conditions from 10C to 70C. Reliable train

detection by sensors exposed to water clogging due to heavy rains.

CLASSIFICATION OF DIGITAL AXLE COUNTER

There are two types in use:

Single Section Digital Axle Counter

Multiple Section Digital Axle Counter


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Single section axle counters are generally used to monitor a single track section i.e there is

only one entry point and one exit point for a particular track section. Digital data is

transmitted directly between two axle counter field equipments by means of modem

communication. Whereas a Multi Section Digital Axle Counter is used to monitor a track

Section confined by multiple Entry and Exit points.

Single Section Digital Axle Counter

General Description

Single Section Digital Axle Counter consists of axle detectors and field units (1 or 2 or 3 or

4) confining a track section connected together by transmission medium which is in VF

range. It is capable of counting axles, count comparison, finding direction of axle movement,

supervision, relay drive and transmission of counts and health of axle detectors and field

units. Track clear indication shall only be given when IN count and OUT count are equal and

equipment is functioning all right. Axle counter shows occupied when any of the its sub-

assemblies belonging to the section is damaged , missing or has become faulty.

The Axle Counter detects change of both amplitude and phase of the axle detector receiver

signal. On Indian Railways Single Section Digital Axle Counters are designed as per RDSO

Specification No. RDSO/SPN/177/2005. The interconnection block diagram for SSDAC is

given on next page.

Communication

For transmission of data between field units, following communication links can be used:

a) Telecomm. Quad cable (0.9 mm. dia.) quad (As per IRS:TC:30/97).

b) PIJF cable (0.9 mm. dia.) 1 pair (IRS:TC 41/97).


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c) OFC One 2 wire voice channel.

Salient Features

It can support upto 4 detection points and generate vital relay outputs for each

detection point.

Each track section can be reset independently from a reset box or with cooperation

from other station depending upon the installation.

The Event logger records all the events occurring in the single section digi tal

axle counter.

It has such an arrangement that wheels of push trolleys, dip lorries, rail dollies

etc. are not counted by it. Trolley protection track circuit is not required with

phase modulation.

Configuration Single Section Digital Axle Counter works in following 5 configurations:

(i) One detection point single section : In terminal lines/siding.

(ii) Two detection points single section: In straight line.

(iii) Three detection points single section: In point zone.

(iv) Four detection points single section: In point zone.

(v) Three detection points for two consecutive sections.


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Main Parts

The SSDAC broadly consists of following parts:

1. Axle detectors.

2. DAC field units.

3. Reset unit.

4. Vital Relay unit.

5. Event logger.

6. Diagnostic system

Functions of various parts

(i) Axle detector

It comprises of two sets of Transmitter/Receiver coils/sensors. These operate at frequencies

above 20 KHz. These are of web mounted type. One detection point comprises a set of two

transmitter and two receiver coils fitted adjacent to each other.

(ii) DAC Field unit

It has 2 out of 2 architecture. It detects and counts axles passing over the axle detector

according to the principle of wheel detection, as well as determine the direction of passing

axles. The field units transmit axle counts and health status to other end field unit and vice-

versa at regular intervals. Provision is available for setting unique address of each field unit.

The address shall be minimum 8 bits.

Principle of wheel detection

The following paragraphs explain the principle of wheel detection:

(a) The train wheel bridges the one set of two Transmitter/Receiver coils of different

frequencies while passing over them and creates an overlapping pulse for Phase detector 1

and phase detector 2 which results in counting of wheels. If phase of signal output of Rx is

compared with Tx then under wheel condition Tx and Rx will be in phase 10V.


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(c) The four spoked trolley wheel, dip lorry wheel and rail dolly wheels do not generate any

pulse due to which the movement of these wheels is ignored. The above principle is

explained in the diagrams given below:

(iii) Reset unitReset boxes are provided in ASM room to reset respective track sections. These work from

24 V DC supply.

If all the field units of an axle counter section are placed in the same station, same/one reset

box can be used to reset all the field units of one section in parallel.

If any field unit of an axle counter section is placed in separate station then separate reset box

is used for resetting that field unit.

The following are provided in the Reset box:1. A six digit (min.) non-resettable type counter.

2. Reset switch with key.

3. Reset push button RED.

4. Axle counter section clear indication (LED 10 mm) GREEN.

5. Axle counter section occupied indication (LED 10 mm) RED.

6. Power OK indication (LED 3 mm) YELLOW.

7. Preparatory reset indication (LED 3 mm) GREEN.

8. Line verification indication (LED 3 mm) YELLOW.


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(iv) Vital relay drive and Relay unit

The vital relays are mounted in the space provided in the relay unit. These are 24 V DC, 1000

ohm plug-in type relays. The pick up and drop contacts of vital relay are utilized for

indicating the axle counter section clear and occupied respectively. The other contacts of vital

relay can be used in interlocking circuits e.g. Signal clearance circuit.

For one detection point single section and two detection point single section configuration,

each field unit drives its vital relay. The field unit of the common detection point mentioned

in 3.4.5 drives two relays of adjacent sections. For three detection point single section and

four detection point single section configuration, vital relay may be provided in any one of

the field units.

(v) Event Logger

The Event Logger is inbuilt in each field unit. It works automatically without any other input

required to be given. It is possible to download logged events to a commercial computer

through standard port. The Event logger shall record following events at the minimum.

Resetting of track section or field unit.

Failures/errors in field units.

Breakdown of communication link(s).

Change in relay status for section occupied/clear.

Change in 5 V output of DC -DC Converter beyond limits.

Change in date/time.

(vi) Diagnostic system

Diagnostic system of the axle counter provides:

Local and remote diagnostics and testing of system through a serial connection.

Self detection of error codes and brief descripti on in reset box through alphanumeric LCD

display.

The same display normally shows in count/out count detection point -wise and section-wise

and software version No. when the system is switched on initially.

After running the diagnostic software, the sys tem data (viz. Current data and Historical

data) can be downloaded and analysed on the PC. The historical data may be used to

reconstruct the sequential occurrence of events happened in the system.

Resetting of Single Section Digital Axle Counter

There are three types of reset applied for a Digital Axle Counter, namely:


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Direct Hard Reset

Direct hard reset shall not be provided normally, which resets the axle counter directly to

clear the axle counter without any verification/co-operation/piloting or out count.

Preparatory Reset

After doing preparatory reset, axle counter continues to show occupied until one train

movement takes place in the section by piloting.

Conditional Hard Reset

This reset is activated after physical verification of clearance of track section from site using

line verification box. The axle counter will show clear after conditional hard reset. Depending

on the application of axle counter, different types of procedures are followed as given in the

following table:

vendor-wise.

(a) A reset operation is only possible when section is occupied or disturbed or there is an

error in the system .

(b) Reset key operation (including line verification switch) should be performed by an

authorized person only.

RDSO approved firms

At present there are three RDSO approved firms for supply and installation of

Single Section Digital Axle Counter on Indian Railways:

1. M/s Eldyne Electrosystems Pvt. Ltd., Kolkata.

2. M/s Central Electronics Ltd., Sahibabad

3. M/s G.G.Tronics, Bangalore

Part C,D & E of this handbook cover axle counters of above firms respectively.


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TYPES OF AXLE COUNTER

Single Section Digital Axle Counter (G36)

We are engaged in offering a wide raneg of best quality Single Section Digital Axle Counter

(G36) to our clients. G36 is a fail-safe 2/2 microcontroller based axle counting system for

section proving in Railways. G36 can be configured to various versions using fool-proof

method thus prevents wrong configuration at site, ensures highest degree of safety. Operating

mode like preparatory, clear and occupied, configuration status, wheel counts and error

messages are constantly displayed on the system LCD status panel and interactive Reset box.

Magnetic sensors detects the axle counts and direction of train movements that is transmitted

to the other end of the system to verify and clear the block. Wheel sensed at one DP willcleared at any DP. The section status can be fed directly to further controlling systems

through vital relay contacts. Each section has two or three detection points based on

configurations. System unit is housed near the track with its DP placed at a variable distance

of 15 Mts.







G36 works on 24 VDC power supply, integrated with lightening surge protectors. Stable

operation at adverse environmental conditions from 10C to 70C. Reliable train detection

by sensors exposed to water clogging due to heavy rains.

Features :

System :

Microprocessor based fail-safe embedded system

Detection of axles and direction of train movement

Fixed pair communication, CRC check & unique addressing of units ensures fail-safety

User friendly GUI aids to download events via RS232 port

Units are housed in location boxes near the tracks


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Axle Detectors :

Web mounted on track, works with 90-R, 52Kg, 60Kg rails

Phase detection principle employed

Signals fed at 21Khz and 25Khz to Tx coils at 60V RMS

Axles above 550mm are detected

Reset Box :

Amended as per RDSO Ver 2.0 Specification

Interactive RESET Box with LCD for live status display of

DP Status (2DP, 3DP, 3DP-2S, AS)

Section Status (Wait for Reset/Preparatory, Section Occupied / Clear)

Wheel Counts (Local and Remote DP)

Multi Section Digital Axle Counter

We are offering a wide assortment of optimum quality Multi Section Digital Axle Counter to

our clients. MSDAC-G39 is a fail safe, reliable and user friendly 2oo3 architecture based

Axle Counter. Complies with RDSO/SPN/176/2005 Ver 2.0. Designed to meet Cenelec SIL-

4 standard EN50126, 50128, 50129, 50159 Part A and B.

Features :

System : Microcontroller based fail-safe embedded system

Upgradable for higher configuration system

Central Evaluator : 2oo3 CPU, 2oo3 Section output and 1oo2 DC-DC Converter power

supply

Complete SMT technology, miniaturized 3U card frame

Fixed pair communication, CRC check with AES128 Cryptography algorithm. Unique

addressing of units ensures fail-safety User friendly GUI aids to configure DPs and Sections


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Units can be housed in location boxes / Mushroom boxes near the tracks

Supports VDU display for monitoring

MSDAC - G39 Card Modules :

MCPU : Central Processing Unit

MDP : DP card supports 2 DP

MSC : Section card supports 1 section

MCE : Communication

MDC : DC-DC Converter

FDP - G39 Field DP system :

FCPU : Central Processing Unit

FCOM : Communication

FPD1/FPD2 : Wheel Detector

FRD : Relay Drive Card

FDC : DC-DC Converter wide range

Axle Detectors :




Supports Axles above 330mm and 550mm (buyer selectable)

Single Section Digital Axle Counter (G36R)


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We are instrumental in offering a wide gamut of supreme quality Single Section Digital Axle

Counter (G36R) to our clients. G36R is a fail-safe 2x2oo2 microcontroller based axle

counting system for High Availability section proving in Railways. G36R can be configured

to various versions using fool-proof method thus prevents wrong configuration at site,

ensures highest degree of safety.Operating mode like preparatory, clear and occupied,

configuration status, wheel counts and error messages are constantly displayed on the system

LCD status panel and interactive Reset box.

Dual Redundant Magnetic sensors detects the axle counts and direction of train movements

that is transmitted to the other end of the system to verify and clear the block. Wheel sensed

at one DP will cleared at any DP. The section status can be fed directly to further controlling

systems through vital relay contacts. Each section has two or three detection points based on


of 15 Mts.







RDSO Approved and Complies with RDSO/SPN/177/2005 Ver 2.0 with amendment 1.

G36R works on 24 VDC power supply, integrated with lightening surge protectors. Stable

operation at adverse environmental conditions from 10C to 70C. Reliable train detection

by sensors exposed to water clogging due to heavy rains.

Features :

System :




User friendly GUI aids to download events via RS232 port Units are housed in location boxes near the tracks


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Axle Detectors :





Dual Reset Box :


Interactive Reset Box with Separate status LCD display for individual axle counting

system on single quad cable multidrop mode and common Resetting

Independent system status and combined parallel Section

Stores events locally to download at station only

Single Section Digital Axle Counter (G39)

We are involved in offering a wide variety of high quality Single Section Digital Axle

Counter (G39) to our clients. G39 is a compact and fail-safe 2/2 microcontroller based axle

counting system for section proving in Railways. G39 can be configured to various versions

using fool-proof method thus prevents wrong configuration at site, ensures highest degree of

safety. Operating mode like preparatory, clear and occupied, configuration status, wheel

counts and error messages are constantly displayed on the system LCD status panel and

interactive Reset box.


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Magnetic sensors detects the axle counts and direction of train movements that is transmitted

to the other end of the system to verify and clear the block. Wheel sensed at one DP will

cleared at any DP. The section status can be fed directly to further controlling systems

through vital relay contacts. Each section has two or three detection points based on


of 15 Mts.

G39 works on 24 VDC power supply, integrated with lightening surge protectors. Reduced

power consumption of 15 watts per DP. Stable operation at adverse environmental conditions

from -10C to 70C. Reliable train detection by sensors exposed to water clogging due to

heavy rains.

Features :

System :




User friendly GUI aids to download events via RS232 port Units are housed in location boxes near the tracks

Axle Detectors :






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Reset Box :


Interactive RESET Box with LCD for live status display of

DP Status (2DP, 3DP, 3DP-2S, AS)

Section Status (Wait for Reset/Preparatory, Section Occupied / Clear)

Wheel Counts (Local and Remote DP)

WHAT IS AXLE COUNTER

An axle counter detection point in the UK

A Modern type axle counter

An axle counter is a device on a railway that detects the passing of a train between two

points on a track. A counting head (or 'detection point') is installed at each end of the section,

and as each train axle passes the counting head at the start of the section, a counter
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increments. A detection point comprises two independent sensors, therefore the device can

detect the direction and speed of a train by the order and time in which the sensors are passed.

As the train passes a similar counting head at the end of the section, the counter decrements.

If the net count is evaluated as zero, the section is presumed to be clear for a second train.

This is carried out by safety critical computers called 'evaluators' which are centrally located,

with the detection points located at the required sites in the field. The detection points are

either connected to the evaluator via dedicated copper cable or via a

telecommunications transmission system. This allows the detection points to be located

significant distances from the evaluator. This is useful when using

centralised interlocking equipment but less so when signalling equipment is distributed at the

lineside in equipment cabinets.

Applications

Track Vacancy Detection

Railway Signalling

The most common use for axle counters is within railway signalling for track vacancy

detection. This is a form of block signalling, which does not permit two trains to be within

the same block at the same time, this decreases the chance of collision due to railways beingdivided into blocks which ensures there is always enough space between trains to allow one

to stop before it hits the one is front.

Railway Crossings

Axle counters are also used for the switching on and switching off of railway crossings.

Closing the crossing to pedestrian and motor vehicles when the presence of a train is

detected, and allowing them to open back up when the successful traverse of the train has

been recorded.

Advantages

Unlike track circuits, axle counters do not require insulated rail joints to be installed. This

avoids breaking the continuity of long welded rails for insulated joints to be inserted.

Axle counters are particularly useful on electrified railways as they eliminate traction

bonding and impedance bonds. Axle counters require no bonding and less cabling in
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comparison to track circuits, and are therefore generally less expensive to install and

maintain.

Axle counters are also useful in instances were there is issues with water on the track.

Generally wheel sensors work under water, as long as the wiring is above the water.

Axle counters do not suffer problems with railhead contamination, e.g. due to rust or

compacted leaf residue, that can affect the correct operation of track circuits. This is because

the operation of axle counters does not rely on the contact of wheel with the rail head to

provide an electrical circuit.

Axle counters are used in places such as wet tunnels (such as the Severn Tunnel) , where

ordinary track circuits are unreliable. Axle counters are also useful on steel structures (such

as the Forth Bridge) , which may prevent the normal operation of track circuits if insulating

the rails from the structure proves impracticable. Axle counters are also useful on long

sections where several intermediate track circuits may be saved. A Thales axle counter

sensor, for example, can be 10,500m from the evaluation unit when connected using the

ISDN communication only, but with the addition of an Ethernet converter the distance is

limited by your transmission system while the latest ALTPRO axle counter sensor model

ZK24 can even go up to 49 km from the unit.

Disadvantages

Axle counters may 'forget' how many axles are in a section for various reasons such as a

power failure. A manual override is therefore necessary to reset the system. This manual

override introduces the human element which may be unreliable. An accident occurred in

the Severn Tunnel and is thought to be due to improper restoration of an axle counter. This,

however, was not proven during the subsequent inquiry. In older installations the evaluators

may use eight-bit logic, causing numerical overflow when a train with 256 axles passes theaxle counter. As a result, this train will not be detected. This imposes a length limit of 255

axles on each train. Modern systems are not restricted by train wheel numbers.

Turnouts

Where there are interlocked turnouts, an axle counter unit needs to be provided for each leg

of that turnout. On lines with non-interlocked/hand operated switches, detection of the switch

points would have to be monitored separately, whereas on track circuited lines misaligned

points can be set to automatically break the track circuit.
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Broken rails

The track circuit provides additional functionality of detecting many, however not all, kinds

of broken rails, though only to a limited extent in AC traction areas and not in the common

rail in DC traction areas. Axle counters offer no such facility. Ordinary track circuits have a

blind spot of about a metre in length from the wiring connections to the insulated joint.

Siding and shunting movements

Axle counters have problems maintaining correct counts when train wheels stop directly on

the counter mechanism; this is known as 'wheel rock'. This can prove problematic at stations

or other areas where cars are shunted, joined and divided. Also, where main lines have

switches to siding, spur or loop tracks extra counters will need to be deployed to detect trains

entering or exiting the line, where with track circuits such infrastructure needs no special

attention.

In Auckland, New Zealand, axle counters have been used on all lines where track circuits are

required except for special places where Hi Rail maintenance vehicles either on or off track.

All road crossing tracks at public level crossings are deemed to be Hi Rail access points and a

short single rail DC track circuit is used. There are also several single rail DC track circuits at

places not at level crossings where Hi Rail vehicles can access the track.

Electromagnetic brakes

Magnetic brakes are used on high speed \ higher speed trains (maximum speed greater than

160 km/h (99.4 mph)). These are physically large pieces of metal mounted on the bogie of the

vehicle, only a few centimetres above the track. They can sometimes be mistakenly detected

by axle counters as another axle. This can happen only on one side of a track block, because

of magnetic field curvature, defects of track geometry, or other issues, leading the signalling

system into confusion and also requiring reset of the detection memory. The modern axle

counters are 'eddy current' brake proof and the magnetic effect of the braking system

described above is overcome, therefore count information remains stable even when a vehicle

fitted with magnetic brakes is braking whilst traversing the rail contacts of a detection point.

Installation

The two main methods of mounting an axle counter is firstly drilling through the rail, this is

seen as time consuming and possible damaging to the rail. However this eliminates the needfor leveling which can help reduce maintenance costs. [
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The second is a rail mount, which clamps to both sides of the rail from underneath it. This

can be seen as quicker and easier to mount in the right conditions, but can mean more often

checks needs to be made to ensure the correct positioning.

Cables

An axle counter cable with a length of 8,000m to 49,000m would typically be buried in a

plastic conduit, which can also be used for CBI cables. The cable in certain situations will

connect to termination boxes every few thousand feet to assist in fault finding, however in

other areas a simple coupler is used to allow speedy installation.

In the case of Frauscher axle counters, the cables have four cores: two for power (positive

and negative), and one each for counting in each direction.

In the case of the ALTPRO ZK24 axle counters, where an ALTPRO VUR module is used,

the cable requires only two cores: power (positive and negative) while the signals from the

axle counter (from the two sensor's heads) are sent back modulated over the very same core

used for the power supply.

Thales AzLM system uses a 2 wire system with DC power and the ISDN telegrams with

counting and head status information on the same wires.

Reset and restoration

There are four methods of securing the reset and restoration of axle counters into service:

Preparatory reset once a Preparatory reset is applied to the system, the axle counter

continues to show the section as occupied until one train movement takes place in the

section, logically if a train has successfully traversed the section, then the section is clear

and the axle counter is set back to unoccupied. [4]

Conditional reset has the section reset only if the last count was in the outward direction.This at least shows that any trains in the section at time of reset were moving out. The

signal protecting the reset section is held at occupied until a sweep or physical

verification of clearance of the track. [4]

Un-conditional reset has the section reset irrespective of the last count action. The

protecting signals are cleared immediately after a reset. In the UK, this type of reset is

used under 'EPR' 'Engineer's Possession Reminder' and a series of procedures are carried

out to ensure the section of line is clear of vehicles and tools before the reset is

performed.
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Co-operative reset requires both the technician and signaller to co-operate to reset and

then restore the section into service. This type of reset is now only used on schemes

which fringe on an existing scheme which utilizes this type of reset arrangement.

Most countries use a variation of the above four methods, sometimes with varying amounts

of automation or human input.

History

The first US patent for an axle counter was filed on 3 June 1960 by Ernst Hofstetter and Kurt

Haas .[ Axle counting initially started with treadle- like mechanisms. They consisted of a

mechanical contact device mounted on the inside of the foot of rail; the wheel flange running

over the device actuated a lever. However they were susceptible to errors and were replaced

in Europe at the end of the 19th Century by hydraulic rail contacts .[6]

Hydraulic rail contacts were actuated by the deflection of the rail caused by axle load running

over the tracks. The first cylinders were filled with mercury; later hydraulic oil was used.

They were then replaced by pneumatically operated switching elements .[6]

In pneumatic axle counting systems, pistons were actuated by specific loads and speeds. They

proved limited in application, and therefore from the 1950s onwards were replaced by

magnetic contacts .[6] Up until that point, Track Circuits always had a big edge when it came to

reliability.

Magnetic contacts were the first contactless switching devices. They were known as "axle

counting magnets". The iron wheel flanges triggered an actuation by interrupting a magnetic

field. Hofstetter and Haas' patent was of this type .[5] During this time, inductive methods were

also being produced based on transformers. During the 1970s, developments in the

electronics field as well as the introduction of integrated circuits allowed the design of the

axle counters currently used. [

PERFORMANCE OF NEW TECHNOLOGIES IN

SIGNALLING SYSTEMS ON INDIAN RAILWAYS

SUMMARY

This paper intends to analyse various aspects of processes and procedures followed on Indian

Railways (IR) during the introduction of new technology based systems in signalling, and

their comparison with the best practices of railways world wide to find out the reason of
http://en.wikipedia.org/wiki/Signalman_(rail)http://en.wikipedia.org/wiki/Axle_counter#cite_note-patent-5http://en.wikipedia.org/wiki/Axle_counter#cite_note-patent-5http://en.wikipedia.org/wiki/Axle_counter#cite_note-patent-5http://en.wikipedia.org/wiki/Treadle_(railway)http://en.wikipedia.org/wiki/Train_wheel#Flangehttp://en.wikipedia.org/wiki/Axle_counter#cite_note-:0-6http://en.wikipedia.org/wiki/Axle_counter#cite_note-:0-6http://en.wikipedia.org/wiki/Axle_counter#cite_note-:0-6http://en.wikipedia.org/wiki/Pneumaticshttp://en.wikipedia.org/wiki/Axle_counter#cite_note-:0-6http://en.wikipedia.org/wiki/Axle_counter#cite_note-:0-6http://en.wikipedia.org/wiki/Axle_counter#cite_note-:0-6http://en.wikipedia.org/wiki/Axle_counter#cite_note-:0-6http://en.wikipedia.org/wiki/Axle_counter#cite_note-:0-6http://en.wikipedia.org/wiki/Axle_counter#cite_note-:0-6http://en.wikipedia.org/wiki/Track_circuitshttp://en.wikipedia.org/wiki/Axle_counter#cite_note-patent-5http://en.wikipedia.org/wiki/Axle_counter#cite_note-patent-5http://en.wikipedia.org/wiki/Axle_counter#cite_note-patent-5http://en.wikipedia.org/wiki/Axle_counter#cite_note-patent-5http://en.wikipedia.org/wiki/Track_circuitshttp://en.wikipedia.org/wiki/Axle_counter#cite_note-:0-6http://en.wikipedia.org/wiki/Axle_counter#cite_note-:0-6http://en.wikipedia.org/wiki/Pneumaticshttp://en.wikipedia.org/wiki/Axle_counter#cite_note-:0-6http://en.wikipedia.org/wiki/Train_wheel#Flangehttp://en.wikipedia.org/wiki/Treadle_(railway)http://en.wikipedia.org/wiki/Axle_counter#cite_note-patent-5http://en.wikipedia.org/wiki/Signalman_(rail)


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dismal performance and inability to leverage new technology to improve reliability and

availability of signalling systems. Instead of bringing enhanced reliability, availability, safety

and peace of mind to maintainers and maintenance managers, these new technology based

equipments and systems have brought uncertainties, fear, helplessness and poor

understanding. The reliability and improvement potential of the new systems compared to the

old systems have been overshadowed by the poor performance often bringing sleepless

nights to the maintenance manager responsible for them. The volume of traffic carried by IR

provides heavy demand for enhanced availability of signalling systems and there is no scope

for compromise. What has gone wrong is the question in the mind of all concerned? This

paper attempts to answer this question after critical analysis of the entire process and its

comparison with the best practices adopted across the industry.

Indian Railways has remained adaptive to new technologies in the field of signalling and

telecommunications since its inception in 1853. Introduction of multiple aspect colour light

signalling, relay interlocking, various kinds of block working, points operation, and train

detection and microwave radios etc has been done as soon as the technology was adopted by

other railways across the globe. Indian railways have adopted these technologies mostly in a

very smooth manner in the past. The operation and maintenance has never been an issue and

most of the systems have been sustained without OEM support. Manufacturing of Block

instruments, GRS point machines and B & Q type relays by various Signal Workshops

owned by IR and full service support to the customers and continuation of Klystron based

microwave radio equipments for the IR system for more than 35 years are positive example

of successful technology induction. However, during the last 10 15 years, the experience of

the introduction of domestic or imported new technology based systems and equipments on

IR have not been very encouraging. During this period, LED based Colour Light Signal

lighting units, Integrated Power Supply System (IPS), Single and Multiple section Digital

Axle Counters, Solid State Interlockings, ETCS level II based Train Protection & Warning

System (TPWS), GPS based Anti Collision Device (ACD) and GSM (R) based train radio

communication systems have been introduced. The trend of the deployment of these systems

is displayed below.


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CONCLUSION

Axle counter is a device for monitoring a specified section of track for the presence of

vehicle. Conventional axle counters were designed with transistorized circuits and ICs. Now

Axle Counters are designed using Micro-Controllers and Software program, and these arecalled as Digital Axle Counters. The communication used in the system is by means of

packets for exchange of information between units. This communication is in duplex mode

and is fail safe. (In duplex mode data is exchanged between two connected devices in both

directions simultaneously. Data flow takes place independently in both directions). An axle

counter is a device on a railway that detects the passing of a train between two points on a

track. A counting head (or 'detection point') is installed at each end of the section, and as each

train axle passes the counting head at the start of the section, a counter increments. Adetection point comprises two independent sensors, therefore the device can detect the

direction and speed of a train by the order and time in which the sensors are passed. As the

train passes a similar counting head at the end of the section, the counter decrements. If the

net count is evaluated as zero, the section is presumed to be clear for a second train.
http://en.wikipedia.org/wiki/Railwayhttp://en.wikipedia.org/wiki/Trainhttp://en.wikipedia.org/wiki/Axlehttp://en.wikipedia.org/wiki/Axlehttp://en.wikipedia.org/wiki/Trainhttp://en.wikipedia.org/wiki/Railway


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REFERENCE

1. "THE DEVELOPMENT AND PRINCIPLES OF UK SIGNALLING". Railway

Technical . Retrieved October 21, 2014.

2. "BO23 Brochure". AltPro . AltPro. Retrieved October 21, 2014.3. "Introduction to Tiefenbach Wheel Sensor Technology". Tiefenbach. Retrieved

October 21, 2014.

4. b "DIGITAL AXLE COUNTER". CAMTECH. April 2010. Retrieved October 21,

2014.

5. to: a b "Axle counter for railroad installations, US 3015725 A". Google patents.

6. to: a b c d Rosenberger, Martin (2012). "Future Challenges to Axle Counting

Systems" (pdf). IRSE. Retrieved October 21, 2014.
http://www.railway-technical.com/sigtxt1.shtmlhttp://www.altpro.com/content/download/440/3886/.../BO23_brochure-EN.pdfftp://ftp.usa.mt.com/pub/indmkg/Wagstaff/IND9R86/WD/Abridged%20System%20Install%20Training%202-10.ppthttp://en.wikipedia.org/wiki/Axle_counter#cite_ref-:1_4-1http://122.252.243.98/Departments/snt/CAMTECH%20Notes/SSDACPart%20A%20Introduction.pdfhttp://en.wikipedia.org/wiki/Axle_counter#cite_ref-patent_5-0http://en.wikipedia.org/wiki/Axle_counter#cite_ref-patent_5-0http://en.wikipedia.org/wiki/Axle_counter#cite_ref-patent_5-1http://en.wikipedia.org/wiki/Axle_counter#cite_ref-patent_5-1https://www.google.co.uk/patents/US3015725?dq=axle+counter&hl=en&sa=X&ei=i80zVOPgCNHnaN-1gZgI&ved=0CCgQ6AEwAQhttp://en.wikipedia.org/wiki/Axle_counter#cite_ref-:0_6-0http://en.wikipedia.org/wiki/Axle_counter#cite_ref-:0_6-0http://en.wikipedia.org/wiki/Axle_counter#cite_ref-:0_6-1http://en.wikipedia.org/wiki/Axle_counter#cite_ref-:0_6-1http://en.wikipedia.org/wiki/Axle_counter#cite_ref-:0_6-2http://en.wikipedia.org/wiki/Axle_counter#cite_ref-:0_6-2http://en.wikipedia.org/wiki/Axle_counter#cite_ref-:0_6-3http://en.wikipedia.org/wiki/Axle_counter#cite_ref-:0_6-3http://en.wikipedia.org/wiki/Axle_counter#cite_ref-:0_6-3http://www.irse.org/knowledge/publicdocuments/3.08%20Rosenberger%20-%20Future%20challenges%20of%20axle%20counting.pdfhttp://www.irse.org/knowledge/publicdocuments/3.08%20Rosenberger%20-%20Future%20challenges%20of%20axle%20counting.pdfhttp://www.irse.org/knowledge/publicdocuments/3.08%20Rosenberger%20-%20Future%20challenges%20of%20axle%20counting.pdfhttp://www.irse.org/knowledge/publicdocuments/3.08%20Rosenberger%20-%20Future%20challenges%20of%20axle%20counting.pdfhttp://en.wikipedia.org/wiki/Axle_counter#cite_ref-:0_6-3http://en.wikipedia.org/wiki/Axle_counter#cite_ref-:0_6-2http://en.wikipedia.org/wiki/Axle_counter#cite_ref-:0_6-1http://en.wikipedia.org/wiki/Axle_counter#cite_ref-:0_6-0https://www.google.co.uk/patents/US3015725?dq=axle+counter&hl=en&sa=X&ei=i80zVOPgCNHnaN-1gZgI&ved=0CCgQ6AEwAQhttp://en.wikipedia.org/wiki/Axle_counter#cite_ref-patent_5-1http://en.wikipedia.org/wiki/Axle_counter#cite_ref-patent_5-0http://122.252.243.98/Departments/snt/CAMTECH%20Notes/SSDACPart%20A%20Introduction.pdfhttp://en.wikipedia.org/wiki/Axle_counter#cite_ref-:1_4-1ftp://ftp.usa.mt.com/pub/indmkg/Wagstaff/IND9R86/WD/Abridged%20System%20Install%20Training%202-10.ppthttp://www.altpro.com/content/download/440/3886/.../BO23_brochure-EN.pdfhttp://www.railway-technical.com/sigtxt1.shtml

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