A

SUMMER TRANING PROJECT REPORT

ON

SIGNALING&TLECOMMUNICATION

IN

INDIAN RAILWAY (NWR)

AT

JAIPUR

SUBMITTED TO: SUBMITTED BY:

MS. NIDHI TIWARI DHARMESH MITTAL

VIT, JAIPUR IVth YR.EC-B(09EVJEC030)

1

ACKNOWLEDGEMENT

Training is one of the important aspects for an engineering student’s carrier. It is basically to

strengthen the practical concepts. During this training student gets acquainted with the latest

technology and recent development.

Firstly, I convey my sincere thanks to all the employees of NORTH WESTERN

RAILWAY, JAIPUR. Their love and guidance are omnipotent and incompatible throughout

the training period. I convey special thanks to Mr. R.A.Saini for providing me the

opportunity to undergo this training and I also express thanks to all hard members for their

help and cooperation.

Dharmesh Mittal(09EVJEC030)

2

PREFACE

Engineering students gain theoretical knowledge only through books. Only

theoretical knowledge is not sufficient for absolute mastery in any field. Theoretical

knowledge in our books is not of much use without knowing its practical implementation. It

has been experienced that theoretical knowledge is volatile in nature; however practical

knowledge imparts solid foundation in our mind.

This report is infecting a summary of, what I have learnt and seen during my training

in “Railway Organization, Kota.” Succeeding chapters give details what I have learnt in

Divisional Railway Manager (DRM) Office, Jaipur

3

TABLE OF CONTENT

S.No Chapter Page No.1. ABOUT INDIAN RAILWAYS

o Railway zoneso Subsidiarieso Technical detailso Train Numbering

2. RAILWAYSIGNALINGo Block signalingo Permissive and absolute blockso Train detectiono Route signaling and speed signaling

3. INTERLOCKINGo ROUTE RELAY INTERLOCKINGo RELAY

4. TRAIN TRAFFIC CONTROLo Railway Control Circuitso TYPE OF CONTROL SYSTEM

5. EXCHANGE AND TEST ROOMo PD MUXo FEATURES

6. COMMUNICATION SYSTEM

o Overhead Communicationo Underground Communicationo MICROWAVE COMMUNICATION

7. MICROWAVE TRANSMISSIONo Propagationo properties of EMo MICROWAVE (MW)

8. OPTICAL FIBREo FIBER CONSTRUCTION o Optical fiber communicationo APPLICATION

9. PASSENGER RESERVATIONSYSTEM o EQUIPMENTS

4

o Workingo Set up in railway

10. UNRESERVED TICKETING SYSTEMo Block Diagram of UTSo UTS NETWORK

11. INTERACTIVE VOICE RESPONSE SYSTEMo Online train information systemo IVRS PC

12. RAILNETo Block diagramo Set up for networking in Indiao Block diagram of Railway networko PASSENGER IN RAILWAY

5

List of Figure

S.No. Name of Figure Page No.1.1 A WAP5 locomotive 91.2 Double Decker Train 102.1 Block Signaling 112.2 Vertical color light signal 143.1 control panel 153.2 Indication Panel 163.3 A DPDT AC coil relay with "ice cube"

packaging17

3.4 Relay interlocking 177.1 Microwave Communication 238.1 Optical fiber 268.2 Fiber Construction 278.3 Optical Fiber Communication 289.1 Set up of mux &demux in railway 3410.1 Block Diagram of UTS 3510.2 UTS Network 36

6

Chapter 1: ABOUT INDIAN RAILWAYS

Indian Railways

Type Departmental Undertaking of The Ministry of Railways, Government of India

Industry Rail transport

Founded 16 April 1857

Headquarters New Delhi, Delhi, India

Area served India

Key people

Mukul Roy(Ministry of Railways)K. H. Muniyappa&BharatsinhMadhavsinhSolanki(Ministers of State)VivekSahai(Chairman, Railway Board)

Products Rail transport, Cargo transport , Services, more...

Revenue 88,355 crore (US$19.7 billion) (2009-10)

Net income 9,595 crore (US$2.14 billion) (2009-10)

Owner(s) Republic of India (100%)

Divisions 17 Railway Zones

7

Website Indianrailways.gov.in

An Indian railway is the central government-owned railway company of India, which owns

and operates most of the country's rail transport. It is overseen by the Ministry of Railways

of the Government of India.

Indian Railways has more than 64,215 kilometers (39,901 mi) of track and 7,083 stations. It

has the world's fourth largest railway network after those of the United States, Russia and

China. The railways traverse the length and breadth of the country and carry over 30 million

passengers and 2.8 million tons of freight daily. It is one of the world's largest commercial

or utility employers, with more than 1.6 million employees. As to rolling stock, IR owns

over 230,000 (freight) wagons, 60,000 coaches and 9,000 locomotives.

Railways were first introduced to India in 1853. By 1947, the year of India's independence,

there were forty-two rail systems. In 1951 the systems were nationalized as one unit,

becoming one of the largest networks in the world. IR operates both long distance and

suburban rail systems on a multi-gauge network of broad, meter and narrowgauges. It also

owns locomotive and coach production facilities.

1.1 Railway zones:

S. No Name Abbr. Date Established Headquarter Divisions1. Central CR 1951, November

5Mumbai Mumbai, Bhusawal, Pune,

Solapur, Nagpur2. East

CentralECR 2002, October 1 Hajipur Danapur, Dhanbad,

Mughalsarai, Samastipur3. East Coast ECR 2003, April 1 Bhubaneswar Khurda Road, Sambalpur,

Visakhapatnam4. Eastern ER 1952, April Kolkata Howrah, Sealdah, Asansol,

Malda5. North

CentralNCR 2003, April 1 Allahabad Allahabad, Agra, Jhansi

6. North Eastern

NER 1952 Gorakhpur Izzatnagar, Lucknow, Varanasi

7. North NWR 2002, October 1 Jaipur Jaipur, Ajmer, Bikaner, Jodhpur

8

Western8. Northeast

FrontierNFR 1958,15th Jan Guwahati Alipurduar, Katihar, Rangia,

Lumding, Tinsukia9. Northern NR 1952, April 14 Delhi Delhi, Ambala, Firozpur,

Lucknow, Moradabad10. South

CentralSCR 1966, October 2 Secunderaba

dSecunderabad, Hyderabad, Guntakal, Guntur, Nanded, Vijayawada

11. South East Central

SECR 2003, April 1 Bilaspur Bilaspur, Raipur, Nagpur

12. South Eastern

SER 1955 Kolkata Adra, Chakradharpur, Kharagpur, Ranchi

13. South Western

SWR 2003, April 1 Hubli Hubli, Bangalore, Mysore

14. Southern SR 1951, April 14 Chennai Chennai, Tiruchirappalli, Madurai, Palakkad, Salem, Trivandrum(Thiruvananthapuram)

15. West Central

WCR 2003, April 1 Jabalpur Jabalpur, Bhopal, Kota

16. Western WR 1951, November 5

Mumbai Mumbai Central, Ratlam, Ahmedabad, Rajkot, Bhavnagar, Vadodara

17. Kolkata Metro

2010, December 25

Kolkata Kolkata Metro

1.2 Subsidiaries

Fig 1.1.: A WAP5 locomotive

Indian Railways manufactures much of its rolling stock and heavy engineering components at its six manufacturing plants, called Production Units, which are managed directly by the ministry. As with most developing economies, the main reason for this was the policy of import substitution of expensive technology related products when the general state of the national engineering industry was immature. Each of these six production units is headed by a General Manager, who also reports directly to the Railway

9

1.3 Technical details:

Track and gauge: Indian railways uses four gauges, the 1,676 mm (5 ft 6 in) broad gauge which is wider than the 1,435 mm (4 ft 8 1⁄2 in) standard gauge; the 1,000 mm (3 ft 3 3⁄8 in) meter gauge; and two narrow gauges, 762 mm (2 ft 6 in) and 610 mm (2 ft) . Track sections are rated for speeds ranging from 75 to 160 km/h (47 to 99 mph).The total length of track used by Indian Railways was about 114,000 km (71,000 mi) while the total route length of the network was 64,215 km (39,901 mi) on 31 March 2011. Broad gauge is the predominant gauge used by Indian railways. Indian broad gauge—1,676 mm (5 ft 6 in)—is the most widely used gauge in India with 102,000 km (63,000 mi) of track length (90% of entire track length of all the gauges) and 54,600 km of route-kilometer(85% of entire route-kilometer of all the gauges) on 31 march 2011.in some regions with less traffic, the meter gauge (1,000 mm/3 ft 3 3⁄8 in) is common, although the unigauge project is in progress to convert all tracks to broad gauge. the meter gauge had about 9,000 km (5,600 mi) of track length (7.9% of entire track length of all the gauges) and 7,500 km of route-kilometer (11.6% of entire route-kilometer of all the gauges) on 31 march 2011.the narrow gauges are present on a few routes, lying in hilly terrains and in some erstwhile private railways (on cost considerations), which are usually difficult to convert to broad gauge. Narrow gauges had a total of 2,400 route-kilometers on 31 marches 2011. the kalka-shimla railway, the nilgiri mountain railway and the Darjeeling Himalayan railway are three notable hill lines that use narrow gauge. Those three will not be converted under the unigauge project.

Fig 1.2: Double Decker train

Double decker AC trains have been introduced in India. The first double decker train was Flying Rani introduced in 2005 while the first double decker AC train in the Indian Railways was introduced in November 2010, running between the Dhanbad and Howrah stations having 10 coaches and 2 power cars.

Sleepers (ties) used are made of prestressed concrete, or steel or cast iron posts, though teak sleepers are still in use on few older lines. The prestressed concrete sleeper is in wide use today. Metal sleepers were extensively used before the advent of concrete sleepers. Indian Railways divides the country into four zones on the basis of the range of track temperature. The greatest temperature variations occur in Rajasthan.

1.4 Train Numbering: Effective December 20, 2010, the railways will deploy a 5 digit numbering system instead of the 4 digit system. The need is due to the fact that the Indian Railways runs 10,000 trains daily. Only a prefix of the digit 1 will be added to the four-digit numbers of the existing trains to make the transition smoother. The special trains run to clear festivals and holiday rush shall have the prefix of 0

10

CHAPTER 2: RAILWAY SIGNALING

Railway signaling is a system used to control railway traffic safely, essentially to prevent trains from colliding. Being guided by fixed rails, trains are uniquely susceptible to collision; furthermore, trains cannot stop quickly, and frequently operate at speeds that do not enable them to stop within sighting distance of the driver.

Most forms of train control involve movement authority being passed from those responsible for each section of a rail network (e.g., a signalman or stationmaster) to the train crew. The set of rules and the physical equipment used to accomplish this determine what is known as the method of working (UK), method of operation (US) or safe working (Aus.). Not all these methods require the use of physical signals and some systems are specific to single track railways.

2.1 Block signaling

Fig: 2.1: Block Signaling

Trains cannot collide with each other if they are not permitted to occupy the same section of track at the same time, so railway lines are divided into sections known as blocks. In normal circumstances, only one train is permitted in each block at a time. This principle forms the basis of most railway safety systems.Entering and leaving a manually-controlled block. Before allowing a train to enter a block, a signalman must be certain that it is not already occupied. When a train leaves a block, he must inform the signalman controlling entry to the block. Even if the signalman receives advice that the previous train has left a block, he is usually required to seek permission from the next signal box to admit the next train. When a train arrives at the end of a block section, before the signalman sends the message that the train has arrived, he must be able to see the end-of-train marker on the back of the last vehicle. This ensures that no part of the train has become detached and remains within the section. The end of train marker might be a white disc by day or a steady or flashing red

11

lamp. If a train has entered the next block before the signalman sees that the disc or lamp is missing, he will ask the next signal box to stop the train and investigate.

2.2 Permissive and absolute blocks:

Under a permissive block system, trains are permitted to pass signals indicating the line ahead is occupied, but only at such a speed that they can stop safely driving by sight. This allows improved efficiency in some situations and is mostly used in the USA.

Permissive block working may also be used in an emergency, either when a driver is unable to contact a signalman after being held at a danger signal for a specific time, although this is only permitted when the signal does not protect any conflicting moves, and also when the signalman is unable to contact the next signal box to make sure the previous train has passed, for example if the telegraph wires are down. In these cases, trains must proceed at very low speed (typically 20 mph or less) so that they are able to stop short of any obstruction. In most cases this will not be allowed during times of poor visibility (e.g. fog or falling snow).

Even when an absolute block system is implemented, multiple trains may enter a block with authorization. This may be necessary e.g. in order to split or join trains together, or to rescue failed trains.

Automatic block: Under automatic block signaling, signals indicate whether or not a train may enter a block based on automatic train detection indicating whether a block is clear. The signals may also be controlled by a signalman, so that they only provide a proceed indication if the signalman sets the signal accordingly and the block is clear.

Fixed block: Most blocks are "fixed", i.e. they include the section of track between two fixed points. On timetable, train order, and token-based systems, blocks usually start and end at selected stations. On signaling-based systems, blocks start and end at signals.

Moving block: One disadvantage of having fixed blocks is that the faster trains are allowed to run, the longer the stopping distance, and therefore the longer the blocks need to be, thus decreasing the line's capacity. Under a moving block system, computers calculate a 'safe zone' around each moving train that no other train is allowed to enter. The system depends on knowledge of the precise location and speed and direction of each train, which is determined by a combination of several sensors: active and passive markers along the track and train borne tachometers and speedometers (GPS systems cannot be used because they do not work in tunnels.) With a moving block, line side signals are unnecessary, and instructions are passed directly to the trains. This has the advantage of increasing track capacity by allowing trains to run closer together while maintaining the required safety margins.

12

2.3: Train detection

Track circuits: One of the most common ways to determine whether a section of line is occupied is by use of a track circuit. The rails at either end of each section are electrically isolated from the next section, and an electrical current is fed to both running rails at one end. A relay at the other end is connected to both rails. When the section is unoccupied, the relay coil completes an electrical circuit, and is energized. However, when a train enters the section, it short-circuits the current in the rails, and the relay is de-energized. This method does not explicitly need to check that the entire train has left the section. If part of the train is left in the section, that part will continue to be detected by the track circuit. This type of circuit is used to detect trains, both for the purpose of setting the signal indication and for providing various interlocking functions — for example, not permitting points to be moved when a train is standing over them. Electrical circuits are also used to prove that points are in the appropriate position before a signal over them may be cleared.

Axle counters: An alternative method of determining the occupied status of a block is using devices located at its beginning and end that count the number of axles entering and leaving. If the same number leaves the block as enter it, the block is assumed to be clear. Although axle counters can provide similar functionality to track circuits, they also exhibit a few other characteristics. In a damp environment an axle counted section can be far longer than a track circuited one. The low ballast resistance of very long track circuits reduces their sensitivity. Track circuits can automatically detect some types of track defect such as a broken rail. In the event of power restoration after a power failure, an axle counted section is left in an undetermined state until a train has passed through the affected section.

Fixed signals: On most railways, physical signals are erected at the line side to indicate to drivers whether the line ahead is occupied and to ensure that sufficient space exists between trains to allow them to stop.

Mechanical signals: Older forms of signal displayed their different aspects by their physical position. The earliest types comprised a board that was either turned face-on and fully visible to the driver, or rotated so as to be practically invisible. While this type of signal is still in use in some countries (e.g. France and Germany), by far the most common form of mechanical signal worldwide is the semaphore signal. This comprises a pivoted arm or blade that can be inclined at different angles. A horizontal arm is the most restrictive indication (for 'danger' or 'caution', depending on the type of signal).To enable trains to run at night, one or more lights are usually provided at each signal. Typically this comprises a permanently-lit oil lamp with movable colored spectacles in front that alter the color of the light. The driver therefore had to learn one set of indications for day time viewing and another for night time viewing. Mechanical signals are usually remotely operated by wire from a lever in a signal box, but electrical or hydraulic operation is normally used for signals that are located too distant for manual operation.

13

Color light signal

Fig:2.2 - Vertical color light signal

On most modern railways, colour light signals have largely replaced mechanical

ones. Colour light signals have the advantage of displaying the same aspects by night as by day, and require less maintenance than mechanical signals.

Although signals vary widely between countries, and even between railways within a given country, a typical system of aspects would be:

Green: Proceed at line speed. Expect to find next signal displaying green or yellow.

Yellow: Prepare to find next signal displaying red.

Red: Stop.

2.4: Route signaling and speed signaling

Signaling of British origin generally conforms to the principle of route signaling. Most railway systems around the world, however, use what is known as speed signaling.

Under route signaling, a driver is informed which route the train will take beyond each signal (unless only one route is possible). This is achieved by a route indicator attached to the signal.

Under speed signaling, the driver is not informed which route the train will take, but the signal

aspect informs him at what speed he may proceed. Speed signaling requires a far greater range of signal aspects than route signaling, but less dependence is placed on drivers' route knowledge.

Safety systems

The consequence of a train driver failing to respond to a signal's indication can be disastrous. As a result, various auxiliary safety systems have been devised. Any such system will necessitate the installation of train borne equipment to some degree. Some systems only intervene in the event of a signal being passed at danger (SPAD). Others include audible and/or visual indications inside the driver's cab to supplement the line side signals. Automatic brake application occurs if the driver should fail to acknowledge a warning. Some systems act intermittently (at each signal), but the most sophisticated systems provide continuous supervision. In-cab safety systems are of great benefit during fog, when poor visibility would otherwise require that restrictive measures be put in place.

.

14

CHAPTER 3: INTERLOCKING

Interlocking: In the early days of the railways, signalmen were responsible for ensuring

any points (US: switches) were set correctly before allowing a train to proceed. Mistakes were made which led to accidents, sometimes with fatalities. The concept of the interlocking of points, signals and other appliances was introduced to improve safety. This prevents a signalman from operating appliances in an unsafe sequence, such as setting a signal to 'clear' while one or more sets of points in the route ahead of the signal are improperly set. Early interlocking systems used mechanical devices both to operate the signaling appliances and to ensure their safe operation. Beginning around the 1930s, electrical relay interlocking were used. Since the late 1980s, new interlocking systems have tended to be of the electronic variety.

3.1 ROUTE RELAY INTERLOCKING (RRI):

The station is interlocked by means of RRI and worked with control Panel located in the RRI cabin. Station is provided with multiple aspects color light signals and electric machine operated points. The entire operation of interlocked points and signal for reception and departure of trains is done through Control Panel by SM on duty,who is responsible for correct & safe working of trains. Reception& dispatch of trains on running lines are controlled by the SM on duty by using operating panel and indication panel. All signals are interlocked with points and are operated fromoperating panel by SM on duty for the reception and dispatch of trains. All running lines are track circuited. The station is provided with Home, Starter, Advanced starter & shunt signals. Main Home signals are provided with calling on signals and shunt signals are below them. Crank Handle interlocking is also provided.

Control Panel:

The control panel has a geographical layout of the entire yard controlled by route relay interlocking.

Indication Panel:

15

All the indications of signals, points setting of the route approach locking and other indications are depicted on the indication panel & provided in front of the SM (panel).

Fig: 3.1: control panel

Fig 3.2: Indication Panel

The SM on duty after performing the required operation on the control panel should watch for the corresponding indication on the indication panel.

Points: All the points in the yard except hand operated points are power operated and worked from the RRI cabin by SM on duty. Motor operated points are numbered from 101 to 200. Hand operated points are numbered from 201 to 250.

Crank handle interlocking: For the purpose of crank handle interlocking and flexibility of movements in the yard the point machines have been grouped into various groups. One crank handle of one group cannot be used on the point machine of another group.

Point indication: Point indication on the indication panel, indicate the posision of points , either lying normal or reverse, if the points are set correctly, steady white light will appear when the track circuit is clear, and steady red light will appear when the track is faulty oroccupied. Failure of the points is indicated by flashing white or red indication depending upon point/track circuit being clear or occupied/failed. In case of point failure lasting for more than 10 seconds, the failure indication ‘p’ lit on the operating panel with a steady red light and audible warning, which can be silenced by operating WXN button on the operating panel.

Track circuit: All track circuits on the indication panel are marked in different colours and are provided with indication lamps. Normally there will be no light on the track portion on the indication panel. When the route has been set for the movement of a train or a shunt movement, continuous white light will be exhibited for the concerned track circuits on indication panel. This indication will change to red as the train occupies the track circuits. After clearance of the track circuit by a train, the indication will turn to white again and will extinguish finally when the route is released. To avoid suppression of track circuit indication

16

, due to lamp failure, the track circuit indicators are having two or more lamps connected in parallel.

3.2 RELAY: A relay is an electrical switch that opens and closes under the control of another

electrical circuit. In the original form, the switch is operated by an electromagnet to open or close one or many sets of contacts. It was invented by Joseph Henry in 1835. Because a relay is able to control an output circuit of high power than the input circuit,it can be considered to be,in a broad sense, a form of an electrical amplifier.

Basic design and operation: A simple electromagnet relay, such as the one taken from a car in the first picture, is an adaptation of an electromagnet. It consists of coil wire surrounding a soft iron core, an iron yoke, which provides a low reluctance path for magnetic flux, a moveable iron armature, and a set, or sets of contacts; two in relay picture. The armature is hinged to the yoke and mechanically linked to a moving contact or contacts. It is held in place by a spring so that when the relay is de-energized there is an air gap in the magnetic circuit. In this condition, one of the two sets of contact in the relay picture is closed, and the other set is open. Other relays may have more or fewer sets of contacts depending on their function. The relay in the picture also has a wire connecting the armature to the yoke. This ensures continuity of the circuit between the moving contacts on the armature, and the circuit track on the printed circuit board(PCB).

Fig3.3-A DPDT AC coil relay with "ice cube" packaging

17

Fig: 3.4: Relay interlocking

CHAPTER 4: TRAIN TRAFFIC CONTROL

4.1 Railway Control Circuits: Railway control circuits are omnibus telephone circuits which provide communication with each train working point, thus facilitating efficient train operation. They should provide satisfactory and reliable communication between the controller and various way side stations, important signal cabins, loco sheds, yard offices etc.

4.2 TYPE OF CONTROL SYSTEM:

According to traffic requirements and to cater to the needs of electric traction area, a section may be provided with one or more railway control circuits as detailed below:

a) Section control / train control: This is provided for communication between the section / train controller in the control office and way side stations, junction station, block cabins, loco sheds and yards in a division for the control of train movements and effective utilization of section capacity.

b) Deputy control: This is provided for communication between the deputy controller in the control office and important stations, junctions & terminal stations, yard master’s office, loco sheds and important signal cabins in a division for supervisory control of traffic operation in general.

c) Traction loco control: Provided between traction loco controller and loco sheds, important station master’s offices for optimum utilization of electric locomotives.

18

d) S&t control: Provided between test room and way stations for effective maintenance of s&tequipment.

e) Emergency control: Provided for selected points along the track routes for establishing communication between train crew (in case of emergency), traction and permanent way staff with traction power controller. The emergency sockets are provided on rail posts at an interval of 1km (max) along the route. They are also provided at FP/SP/SSPS isolators in yards and near bridges.

f) Emergency wireless control communication: The following equipment can also be utilized for emergency wireless communication where such system exists:-

i). Handsets for mobile train radio communication (MTRC) in sections.

ii). Walkie-talkie sets in sections where VHF communication from train to control office has been provided in lieu of any physical medium or MTRC.

19

CHAPTER 5: EXCHANGE AND TEST ROOM

5.1 PD MUX (PRIMARY DIGITAL MULTIPLEXER): CMUX 128 provides a cost

effective solution for the interconnection of a whole range of voice and data interfaces

required in communications networks, where multiple locations are connected over fat

pipes and a small pipe has to be dropped at each location. Large enterprises like railways,

army and utility companies who own their own networks are users of thisproduct segment.

5.2 FEATURES:

Economical, Scalable and Reliable

The unit can be easily configured as a Terminal, Drop Insert, Non-blocking or

Branching/Cross Connect Multiplex, simply by installing the appropriate cards in the

shelf. The multiplexer has cards which support a wide variety of interfaces. Channel cards

are available for voice and data applications. The software-controllable concept enables a

powerful method for configuring the equipment. The flexibility of the CMUX 128

provides network operators the ability to configure all performance parameters, including

time slot assignment, gain level and data transmission parameters either locally, using a

PC/Laptop, or via the network. In both cases user-friendly software enables

reconfiguration at any time, should the requirements for voice and data transmission grow

or change. All the settings are stored in a non-volatile memory that retains information

even in power-down conditions.

Abundant Applications

As a multi-service solution, the CMUX 128 can be used for voice or data access in public

and private networks. It combines E1 network lines with G.703, RS232, V.35, E&M,

FXS, and FXO client interfaces in a compact package.You can configure the CMUX 128

in a variety of ways, from simple primary multiplexer for drop and insert functionality to

sophisticated digital cross-connect for concentration and grooming. Its Voice application

modules such as E&M, FXS and FXO support telephony connections to POTs or private

branch exchanges (PBX). These modules also support networking between a PBX to  

central office (CO), and a PBX to another PBX using tie lines. They can also provide

extensions for telephones in remote 'points of presence' (POPs) or branch offices, as well

20

as modem or fax terminals. In addition to its versatility of application in public

telecommunication networks, the CMUX 128 is ideal for use by utility companies like

railways, electricity, oil, gas and mining and for private telecommunication networks.

Easy to install and economical to maintain, the versatility and features of the CMUX 128

position this MUX as the ideal choice for meeting today's changing network needs.

Redundant Architecture

The CMUX 128 uses a distributed architecture design. This removes the inherent

limitations of centralized architecture, providing a scalable system with no single point of

failure. Users can choose the level of network availability required for their application

through various redundancy options. In the CMUX 128, the CPU redundancy (1:1) and

power supply redundancy (1:1) protect against hardware failures. The E1 facility

redundancy protects against network failures as the CMUX128 can switch traffic to an

alternate facility in the event of a link failure.

Voice and Data Flexibility

There are a total of 20 slots available in the chassis of which 2 slots are reserved for the

CPU cards and another 2 slots are reserved for the power supply unit. The remaining 16

slots can be used for installing access cards. The unit supports a wide variety of interface

options including Voice cards (FXS, FXO, E&M), Data cards (64kbps co-directional,

V.24, V.35, X.21, Ethernet, nx64kbps) and Network cards (E1). The unit comes in a

compact, metal chassis of 3U height, which uses a minimum amount of rack space.   All

cards are fully configurable and have remote diagnostics through the CMUX 128 user

interface. Using these flexible configuration options, the MUX can be deployed in

integrated voice and data networks across the globe.The unit comes in a compact, metal

chassis of 3U height, which uses a minimum amount of rack space.   All cards are fully

configurable and have remote diagnostics through the CMUX 128 user interface. Using

these flexible configuration options, the MUX can be deployed in integrated voice and

data networks across the globeBasicallypd mux is a device which serves both as

modulator, demodulator and multiplex signals. It converts electric signal to digital signal.

CHAPTER 6: COMMUNICATION SYSTEM

Communication means sending and receiving of signal between two stations through different mediums. It plays a vital role for any system and becomes lifeline for the

21

concerned people who were being benefited for the system. In communication system there are three essential components that should be considered:-

Sending (Tx)

Receiving (Rx)

Medium

This system is classified into various types according to the upgradation of technology in the communication system from time to time.

6.1 Overhead Communication: Overhead communication is the most ancient and traditional method of communication that was practice during early times. It includes bamboos and poles which wires were transferred over a long distance.

Drawbacks

Thefts No secrecy Faults due to contact, earth crust, break etc. Limitations of circuits

6.2 Underground Communication:

After the limitations found in overhead communication, a new technology was found i.e cable system that means a bunch of conductors that were used for the signal transfer. These cables laid by digging the ground approximated to 1 km. There are made several junctions at certain distances (25km) so that the effective transfer of signal may be checked.

DRAWBACKS

Total interruption with any fault(cut water entered) Theft Joining is difficult Equipment cost high.

6.3 MICROWAVE COMMUNICATION: Microwave communication brings revolutionary changes in the field of railways communication system. It can be also termed as “Renaissance” for the whole communication channel.

RECEIVING SIDE:

22

Fig 7.1: Microwave Communication

The system modulation plans conforms to standard CCITT modulation plan. The standard CCITT super groups one through 600 channels. 12 channel in 12 to 60 kHz frequency hand make up the CCITT group A. Two additional channels are available between 4kHz and 12 kHz. This system also conforms to the CCITT modulation plan with respect to the erect and inverted sideband orientation. The erect sidebands required for channel in group A and in subgroup 2 are derived by using channels carries below 4.896 Mhz first carrier frequency. Switch setting for S1,S2,S3, CCITT channel designation baseband frequency carrier frequency, carrier frequency, divider number and the test tone frequency are provided in this channel.

From antenna HF

Waveguide & switching

deviceVF

Radio Multiplexer

23

CHAPTER 7: MICROWAVE TRANSMISSION

INTRODUCTION

Radio communication involves:

The modulation of information (data to be sent) & generation of RF power by the radio transmitter.

Radiation of generated RF power into free space by transmitting antenna, RF power transmitted in the form of electro waves to distant destination. Reception of electromagnetic waves at destination by the receiving antenna. The recovery of the information at the destination by the help of the radio receiver.

7.1 Propagation:

In radio communication, the radio transmitter & distant radio receiver is coupled through space. The free space forms the highway for the transmission of the electromagnetic energy.

The radio transmitter is a generator of power. The generated power is radiated to the free space by the antenna in the form of EM energy. This energy is received by the receiving antenna located at the distant then the transmitted information is receipted by the receiver.

7.2 The properties of EM waves are as follows:-

The direction of electric field and magnetic field are perpendicular to each other as well as the direction of propagation.

They travel with the velocity of light they can propagate in free space and vacuum.

Their behavior corresponds to light waves.

7.3 MICROWAVE (MW)

Indian railway has allocated the frequency band of 7.125 GHz to 7.425 GHz.

24

At present the microwave communication is largely employed for long multichannel communication system. This is fixed communication with higher degree of reliability with large channel capacity.

ADVANTAGES OF MICROWAVE COMMUNICATION:-

Large bandwidth is possible. Hence, more information can be transmitted as hundreds of channel is possible (approx 960).

Better quality of service due to negligible voice.

25

OPTICAL FIBRE

The installation and termination of optical fibers used to be regarded as somewhat of a ‘Black art’ but with standardization and easier terminating techniques no longer true. A basic knowledge of the subject, together with a quick lesson and some practice can get you started in fiber optics, but to really understand the subject and gain full in depth knowledge will require some formal training. There are lots of fiber optics training companies offering recognized qualifications and a quick search on the net should fine one in your area. If you are in the UK, optical Technology Limited offers several different courses to choose from including a City & Guides qualification.

There are also hundred books on fiber optics and a search on the Barnes and Noble web site will find nearly 600 titles. Without reviewing them all it is difficult to know what to recommend, but two of the best sellers in this category seem to follow on quite nicely from this page without getting too involved with mathematics.

Fig 8.1: Optical Fiber

THE ADVANTAGES OF USING FIBRE OPTICS

Because of the low loss, high bandwidth properties of over fiber cable they can beused over greater distances than copper cable would be impractical, and by using multiplexors one fiber could replace hundreds of copper cables. This is pretty impressive for a tiny glass filament, but the real benefits in the data industry are its immunity to Electro Magnetic

26

Interference(EMI), and the fact that glass is not an electrical conductor. Because fiber is non-conductive, it can be used where electrical isolation is needed, for instance between buildings where copper cable would require cross bonding to eliminate differences in earth potentials. Fibers also pose no threat in dangerous environment such as chemical plants where a spark could trigger an explosion.

Fig 8.2: Fiber Construction

FIBER CONSTRUCTION

There are many different type of fiber cable, but for the purposes of this explanation we will deal with one of the most common types 62.5/125 micron loose tube. The number represent the diameters of the fiber core and cladding, these are measured in microns which are millionths of a meter. Loose tube fiber can be indoor or outdoor cables usually have the tube filled with gel to act as a moisture barrier which stops the ingress of water. The number of cores in one cable can be anywhere from 4 to 144

WHAT’S THE DIFFERENCE BETWEEN SINGLE-MODE AND MULTI-MODE?

With copper cable larger size means less resistance and therefore more current, but with fiber the opposite is true. To explain this we first need to understand how the light propagates within the fiber core.

LIGHT PROPAGATION: Light travels along a fiber cable by a process called Total Internal Reflection (TIR) this is made possible by using two type of glass which have different refractive indexes. The inner core has a high refractive index and the outer cladding has a low index. This is the same principle as the reflection you see when you look into a pond. The water in the pond has a higher refractive index than the air, and if you look as it from a shallow angle you will see a reflection of the surrounding area

27

Optical fiber communication: Optical fiber is generally made of glass and it is

made into thin fibers of hair’s size. It is a non-metallic conductor and this can transmit light energy from one end to the other end by utilizing the phenomenon of ‘TOTAL INTERNAL REFLECTION OF LIGHT ‘ in conventional cables(copper cables) electric energy is transmitted through metallic conductors. An optical fiber communication system consists of a transmitter which converts the multiplexed electrical signal into an optical signal. A source of light launches the optical signal through a coupler. The fiber carries this signal to the receiver where another coupler couples the light from the fiber to the detector. The transmitter uses either a LASER DIODE or a LIGHT EMMITING DIODE(LED) for electrical to optical conversion. The receiver uses either a PIN Diode or an

Transmitter

Optical fiber

Receiver

Fig 8.3: Optical Fiber Communication

AVALANCHE PHOTO DIODE (APD) for optical to electrical conversion. Long lengths of cable are joined by splicing the fibers.

LIMITATIONS IN USING OPTICAL FIBRE CABLES

a) Difficulty in splicing (jointing).

Modu-lator

D/A converter

De-modulator

A/D CONVERTER

28

Regenarator

Modulator

D/A converter

De-modulator

A/D CONVERTER

Regenerator

b) Highly skilled staff would be required for maintenance.c) Precision and costly instruments would be required.d) Tapping is difficult. In railways difficulty for tap it for emergency and gate

communication.e) Costly if under-utilized.f) Special interface equipment required for block working.g) Accept unipolar codes i.e. return to codes only.

APPLICATION OF OPTICAL FIBRE COMMUNICATION IN RAILWAYS

a) Long haul circuits for administrative branch and data transmission circuits (PRS,FOIS etc.).b) Short haul circuits for linking of telephone exchanges.c) Control communicationd) Signaling application for safe transmission.

PASSENGER RESERVATION SYSTEM (PRS)

29

Introduction:The Passenger Reservation System (PRS) is computerized reservation system for any train from anywhere in country. This system has made the train journey quite comfortable. When PRS system was not developed a station could give the reservation to the customer.Those train which get started from their station but after PRS get installed the customer can get information about any train running in India.The other facilities, which are offered by the PRS system, are the PNR enquiry and the train accommodation availability .The system works both on the optical fiber cable and the microwave communication at the data rate of 4.8 kbps or 9.6 kbps. The microwave system is the standby medium of the data transfer and the optical fiber communication system is used as the main transmission path. The main system is programmed according to the types and trains and compartments.There are mainly 4 servers in India. These are in New Delhi, Kolkata, Chennai, Mumbai and Secundrabad.

EQUIPMENTS

The equipment used in PRS are:

Modem Multiplexing equipment End terminal

Modem

Modem are used for communication various computers or between computers and terminals over ordinary or leased telephone lines. We can use modems to log on to micro, mini, main frame computer for line processing. We can use them to connect two remote computers for data.

Working

Modem means modulate and demodulate. Computer communicates in digital language while telephone lines communicate in analog language. So an inter mediator required which can communicate in both these language and hence Modem plays important role.

Modem transmits information between computers bit by bit by one stream .to represent a bit modem modulates the characteristics of the wave that are carried by telephone lines.

The rate at which the modem changes these characteristics determines the tramission speed of the data transmission .the rate of modem is called bound rate of modem.

30

The bound rate of modem is bits per second .in advance modulation such as quadrature amplitude modulate 4 bits and transmitted it in each band .thus the speed of the modem transmitting at 600 bands would be 2400 bps.

The modem can transmit data in two formats that is asynchronous and synchronous.

For critical application users may sometime lease a second line and keep it as a stand by link. if the main link fails, personnel at both ends of the circuits switch user equipments (multiplexer and router) to the stand by link. The analog modem switch at each location is connected to analog modems of main as well as stands by links.

If the main links fails the switch units at either end switch the user equipments at the stand by link. When the main links get restored the analog modem switches the user equipments back to the main link.

Multiplexing

It is the process of converting multi inputs signal into one output signal is known as multiplexing. S0 s1

I0

I1 output

I2

I3

I4

Two types of data are there for transmission. They are

1) Analog dataFDM (Frequency division multiplexing)

2) Digital dataTDM (Time division multiplexing).

For speech frequency range is .3-3.4 kHz i.e. approx 0-4 kHz.

For acknowledgement telephone range of 3.85 kHz frequency is generated.

Suppose we have used 30 channels out of which 15 are in use and other 15 are ideal so in order to resolve this problem is to use statistical multiplexing.

MUX

31

In case of statistical multiplexing we have dynamic slotting .in this case we use either 8 or 16 port mux and time slots are allotted dynamically.

The data is get multiplexed at the rate of 96 kbps. The multiplexer is generally of analog type.

Modulation

Process of changing the characteristic of carrier with respect to the baseband signal is called modulation.

PCM: Pulse code modulation. It is the process of transferring the digital data through fiber.

The analog data is first converted into digital data.

1. Sampling2. Filtering3. Quantization

32

Set up in railway

Fig 9.1: Set up of mux &demux in railway

End terminal

The end terminal of the system is the station where tickets are to be printed out. The terminal consists of a company system with a dot matrix printer the no. of the total end terminal at the station can be increased or decreased according to the multiplexer used.

M

U

xModem

Modem

De

M

U

x

Pc

33

UNRESERVED TICKETING SYSTEM (UTS)

Introduction: The Universal ticketing system (UTS) is a computerized system used to issue the tickets for the unreserved compartments of train .the system is programmed according to the type of the train.The whole system can be controlled remotely by the CRIS, Mumbai CST. The system works at the data rate of the 64 kbps .therefore for such a high data the optical fiber communication system it has been setup from different directions.

Equipment’s overview

Block Diagram of UTS:-

Fig 10.1: Block Diagram of UTS

The various equipment used are:-

Terminal and terminal server Baseband modem Router

Terminal and terminal server: It is the end point of the network from where tickets are to be printed out .It consists of a monitor, a keyboard and a matrix printer. The whole system is connected to the terminal server, which determines the number of terminals through a data cable.

Baseband modem: this device is used to interconnect user devices with each other over 2-wire circuits. The ports available for the interfacing are G-703, V.35, V.24, V.11.the power supply option include 230 V or -48 V dc operated supplies. The coding of data is also done

Terminal Terminal server

Terminal

Baseband modem

Router

RouterBaseband modem

Terminal server

PCM-TDM

Network

34

by baseband modem. Router is used to detect the quality samples from different branches and start sending data from that branch which has good quality ratio. The router does this selection and rejection of branches. The router has 25 input terminals, which means that 25 branches can be connected to the router.

UTS NETWORK

Fig 10.2: UTS Network

INTERACTIVE VOICE RESPONSE SYSTEM (IVRS)

NDLS

NR L3 ROUTER

L-3 SWITCH

UTS/PRS

RE

SIKR

BKI

RGS

KRH

AWR

NK

I/II

LAVI II

DPR

GII

KS

JJN

FL

GOJ

DO

35

INTRODUCTION

The IVRS is the arrangement of a computer and a telephone set. In this system interactive between telephone and computer are done and the results are in the form of voice. It is now used at the place where enquiry is required e.g. banks, mobile companies etc.

In railway it is used in “online train information system” and “passenger reservation enquiry system”.

Online train information system: - By this system the status of any passenger, mail, and express train can be collected from any station for their punctuality and running position. The system consists of DATA ENTRY PC which is installed at every control office in WCR. This system is doing activity:-

It consists complete data regarding time table of the section including arrival/departure of each train at important station.

Status of train for particular time is available and status is updated at every 15 minute. The data entering operator is just entering the correct expected time of train. Then data entering PC formats the data of file and makes correction of folder.

The same file then deposited in gueue directory which can be controlled by main controlling DATA entry PC BCT and ADI through lease line modem connectivity.

IVRS PC:- the station where the data of data entry PC is required for use of enquiry then another personnel computer is connected called IVRS PC .IVRS PC get connected to telephones line through dialog card.

Dialog card can be of 4 line, 12 line or 30 line with costs of rs 75000 and E1 costs rs 200000. So a roll costs of IVRS is around rs 3 lakh or more.

The software used is IVRS PC is user friendly with following facilities:-

Setting of ring. Selection of operation on tone/pulse. Running of special message. Recording of special message. Support more than one language. Summary of received calls.

The basic hardware’s required for IVRS system are:-

Telephone set.

36

Computer system. Amplifier Multiplexing equipment Connecting wires and cables

RAILNET

INTRODUCTION

37

Rail net is an internet for railways. The rail net is a railway open system for quick data transmission and data using resources at different places. it is purely under railway and information and data are collected at the headquarter through different divisions and unit consists of main switch ,web server , switch, hub, router, modem, LAN and WAN extenders and pc’s that are considered as the nodes . day to day report of each division are send to the headquarter to Delhi. There are several advantages of rail net in railways in different fields such that important information and data can be transformed from one division to other division. Within less time in railways current position of train can be obtained in PRS. The connectivity of different reservation take place with the help of rail net and e-mail can be sent to a fax machine etc.

Rail net is nothing but an interconnection and infrastructure medium of different railway zone and division in the Indian railway

Block diagram of technologies:-

In rail net wide area network is used .Typically WAN consists of no. of interconnected switching nodes. A Trans from any one device is routed through these internal nodes to the

TECHNOLOGY

LAN WAN

BUS RING TREE STAR

TOPOLOGIES

38

specific destination device. Wan connect network across longer distances, such as between cities or across continents.

Set up for networking in india

DELHI JAIPIR JAISALMER

DCM:-Refers to data compression mux.

PRS:-Passenger reservation system

In Indian railway there are only 5 servers all over INDIA. They are further connected to other stations such as Jaipur, lucknow etc.

Set up of 5 servers and there mesh connection

D

C

M

A

C

39

I II

III IV

V

EXAMPLE:-Puja express train no. is

2304-DELHI to HAWRAH 2303-HAWRAH to DELHI

NEW DELHI

JAIPUR

MUMBAI

HAWRAH

SECUNDRABD

MADRAS

40

Now if one has to confirm ticket for 2301 then it can be confirmed from DELHI’s server.

But if one has to confirm ticket for 2303 and if Howrah’s server is down then the ticket cannot be confirmed from DELHI’s server.

Moreover if any one of the server is down out of 5 server then it cannot confirm ticket from itself and from all the connected to it until the problem is resolved.

There is a device called dumb terminal. It is exactly like pc but with a slight difference that it does not contain any memory or hard disk for storage of data. If in any case one requires any data then dumb terminal send that information related to that data to the server and then printout can be taken out .The work of dumb terminal is only for ticketing purpose.

VT 100, VT 52220, 320 is the ratings of video terminal.

Railway network

Block diagram

41

1) ETHERNET DATA >10MBPS2) SERIAL 3 WIRES (Transmitting. Receiving and Ground)

ETHERNET:-

tx+ tx- rx+ rx-

PRS UTS

MODEM MODEM

MUX MUX

TERMINAL SERVER TS

SWITCH

ZONAL ROUTER NWR

ABUROAD

ALWARJAIPUR

DAUSA

42

The above diagram shows transmission of data in a 2 wire line. Now tx+ is connected with rx+ and txt- with rx- otherwise transmission of data is not possible.

TOUCH SCREEN Y

GRID

X

It is the screen which is placed in front of the monitor. It acts like a mouse for the reservation or waiting position by customers.

PASSENGER IN RAILWAY

RESERVATION (PRS) UNRESERVED (UTS)

BEEP THE TICKET

CANCEL

CONFIRM WAITING43

In BANGLORE MUESUEM there is 6000 pair of wire which is world’s largest cable wire. It was made by Hindustan cable limited.

It was not used even once since it was made because soon after its invention control cable wire was invented.

44

45