A SEMINAR REPORT

ON

6 WEEK INDUSTRIAL TRAINING IN EAST CENTRAL RAILWAY (ECR)

HAJIPUR HQ

SIGNAL & TELICOMMUNICATION DEPARTMENT

SUBMITTED BY:

SANJEET KUMAR

REGISTRATION NO.-1308143

BRANCH:-ELECTRICAL & ELECTRONICS ENGINEERING

UNIVERSITY:-PUNJAB TECHNICAL UNIVERSITY

KAPURTHALA JALANDHAR (PUNJAB)-144020

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Abstract

This report takes a pedagogical approach in demonstration of communication system and

signal transmission throughout the machinery of railways. An effort to a significant

insight into the working of the devices of railways from view point of communication has

been made. The focus of this detailed study is divided into two aspects:

Telecommunication and Signaling. Besides, various communication systems are currently

being employed in the Indian railways. Factors like safety and reliability concerns are

discussed further. The design and architecture of various information systems are also

furnished. The detailed analysis is directed towards control logic for the railway

interlocking, type of communication protocols upon which the control systems depends.

Telecommunication part has been also discussed to make the report more comprehensive.

A newer improvement towards Centralized Traffic Control has also been highlighted for

the railway system to prove itself a reliable option for its travelers.

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Acknowledgement

We take this opportunity to express our profound gratitude and deep regards to our guide

Rajesh Sharan Sir (ASTE/UTS) for his exemplary guidance, monitoring and constant

encouragement throughout the course of this training. The blessing, help and guidance

given by him time to time shall carry us a long way in the journey of life on which we are

about to embark.

 We also take this opportunity to express a deep sense of gratitude to Pramod Sir, for his

cordial support, valuable information and guidance, which helped us in completing this

task through various stages.

 We are obliged to Ravi Prakash Sir (SSE, Hajipur HQ), Mukesh Sir, Raj Kumar Sir, and

Pramod Sir and also thankful to the staff members of Hajipur HQ, Sonpur Jn. And

Danapur Division for the valuable information provided by them in their respective fields.

We are grateful for their cooperation during the period of our training.

 Lastly, we thank Almighty, our parents and our accompanying friends for their constant

encouragement without whom this training would not have been possible.

 

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Table of Contents

1Introduction...........................................................................................4

2Telecommunications............................................................................5

2.1 Optical Fiber Communications...................................................................................5

2.2 Quad Cable................................................................................................................. 9

2.3 PA Systems................................................................................................................10

2.4 Telephone Exchange..................................................................................................11

2.5 Mobile Communications............................................................................................14

2.6 FOIS...........................................................................................................................23

2.7 COIS...........................................................................................................................24

2.8 Internet……………………………………………………………………………....25

2.9 PRS………………………………………………………………………………….28

2.10 Control System…………………………………………………………………….29

3Signaling..............................................................................................30

3.1 Basic Signaling……………………………………………………………………....31

3.2 Interlocking…………………………………………………………………………. 32

3.3 PI and RRI……………………………………………………………………………34

3.4 EI……………………………………………………………………………………...36

3.5 Centralized Traffic Control…………………………………………………………...38

Summary................................................................................................40

References……………………………………………………………………………..41

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1 Introduction

Indian Railways is one of the largest Railways in the world. Introduced in 1853 the

Railway network in India spread and expanded rapidly and has become the principal

mode of transport in the country. It has also absorbed advances in railway technology in

tune with the requirement of moving large volumes of passenger and the freight traffic.

Railways were first introduced to India in 1853 from Bombay to Thane. In 1951 the

systems were nationalized as one unit, the Indian Railways, 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 narrow gauges. It also

owns locomotive and coach production facilities at several places in India and are

assigned codes identifying their gauge, kind of power and type of operation. Its

operations cover twenty four states and three union territories and also provides limited

international services to Nepal, Bangladesh and Pakistan.

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2 Telecommunications

Telecommunication in the modern era is the science and practice

of transmitting information by electromagnetic means.

In earlier times, telecommunications involved the use of visual signals, such

as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or

audio messages such as coded drumbeats, lung-blown horns, and loud whistles. In modern

times, telecommunications involves the use of electrical devices such as

the telegraph, telephone, and teleprinter , as well as the use of radio, microwave

transmission towers, fiber optics, orbiting satellites and the Internet, which is a vast

world-wide computer network.

A revolution in wireless telecommunications began in the first decade of the 1900s with

pioneering developments in radio communications by Nikola Tesla and Guglielmo

Marconi.

2.1 Optical Fiber Communications

Fiber-optic communication is a method of transmitting information from one place to

another by sending pulses of light through an optical fiber. The optical fiber acts as a low

loss, wide bandwidth transmission channel. A light source is required to emit light signals,

which are modulated by the signal data. To enhance the performance of the

system, a spectrally pure light source is required.

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CONSTRUCTION OF OPTICAL FIBER 

In the late 1970s and early 1980s, telephone companies began to use fibers extensively

tore build their communications infrastructure. According to KMI Corporation, specialists

in fiber optic market research, by the end of 1990 there were approximately eight million

miles of fiber laid in the U.S. (this is miles of fiber, not miles of cable which can contain

many fibers). By the end of 2000, there were 80 million miles in the U.S. and 225 million

worldwide. Copper cable is increasingly being replaced with fibers for

LAN backbones as well, and this usage is expected to increase substantially.

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A thin glass strand designed for light transmission. A single hair-thin fiber is capable of transmitting trillions of bits per second. In addition to their huge transmission capacity, optical fibers offer many advantages over electricity and copper wire. Light pulses are not affected by random radiation in the environment, and their error rate is significantly lower. Fibers allow longer distances to be spanned before the signal has to be regenerated by expensive "repeaters." Fibers are more secure, because taps in the line can be detected, and lastly, fiber installation is streamlined due to their dramatically lower weight and smaller size compared to copper cables.

Fig 1: OFC cables

Pure Glass

An optical fiber is constructed of a transparent core made of nearly pure silicon dioxide

(SiO2), through which the light travels. The core is surrounded by a cladding layer that

reflects light, guiding the light along the core. A plastic coating covers the cladding

to protect the glass surface. Cables also include fibers of Kevlar and/or steel wires

for strength and an outer sheath of plastic or Teflon for protection. 

 

Enormous Bandwidth

For glass fibers, there are two "optical windows" where the fiber is most transparent and

efficient.The centers of these windows are 1300 nm and 1550 nm, providing

approximately 18,000GHz and 12,000GHz respectively, for a total of 30,000GHz. This

enormous bandwidth is potentially usable in one fiber. Plastic is also used for short-

distance fiber runs, and their transparent windows are typically 650 nm and in the 750-900

nm range.

Single mode and Multimode

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Fig 2: Inner Sections of OFC cable

There are two primary types of fiber. For intercity cabling and highest speed, single mode

fiber with a core diameter of less than 10 microns is used. Multimode fiber is very

common for short distances and has a core diameter from 50 to 100 microns. See laser,

WDM, fiber optics glossary and cable categories.

The light in a fiber-optic cable travels through the core (hallway) by constantly bouncing

from the cladding (mirror-lined walls), a principle called total internal reflection. Because

the cladding does not absorb any light from the core, the light wave can travel great

distances. However, some of the light signal degrades

Within the fiber, mostly due to impurities in the glass. The extent that the signal degrades

depends on the purity of the glass and the wavelength of the transmitted light.

Applications

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Fig 3: Diagram of total internal reflection in an optical fiber 

Optical fiber is used by many telecommunications companies to transmit telephone

signals, Internet communication, and cable television signals. Due to much

lower attenuation and interference, optical fiber has large advantages over existing copper

wire in long-distance and high-demand applications. However, infrastructure development

within cities was relatively difficult and time-consuming, and fiber-optic systems were

complex and expensive to install and operate. Due to these difficulties, fiber-optic

communication systems have primarily been installed in long-distance applications, where

they can be used to their full transmission capacity, offsetting the increased cost.

2.2 Quad Cable

Conductor: Each conductor consists of round wire of annealed high conductivity

copper.

Insulation: Each conductor is insulated with solid medium/ high density polyethylene

insulation.

Quadding: Four insulated conductors stranded to form a star quad, two conductors

diagonally opposite forming one pair and the remaining two diagonally opposite

conductors forming the second pairs of the quad.

Laying Up: The quads are assembled to form a symmetrical core with a right hand lay.

Polyethylene strungs of required diameter may be used as fillers, if necessary, for

proper circular core formation.

Filling and core wrapping: The cable core is fully filled with water resistant

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Fig 4: Inner sections of a quad cable

compound which is compatible with the polythene insulation of the conductors. The

filled cable core is wrapped with at least one helical or longitudinally polythene tape.

Poly-Al Laminate Moisture Barrier: Aluminum tape, coated with polythene on

both sides is applied longitudinally over the cable core with a specified overlap. The

taoe is seased and bonded to the inner surface of the polythene sheath.

Sheathing: The screened cable core is sheathed with black polythene compound.

Screening and protection: The cable core with inners sheath is surrounded by a

reasonably close fitted screen of Aluminum in the form of wires/strips/welded

aluminum tubing. The aluminum screen is wrapped with a single layer of woven tape

impregnated with Barium chromate with a specified overlap.

2.3 PA Systems

A public address system (PA system) is an electronic sound amplification and distribution

system with a microphone, amplifier and loudspeakers, used to allow a person to address

a large public, for example for announcements of movements at large and noisy air and

rail terminals.

The term is also used for systems which may additionally have a mixing console, and

amplifiers and loudspeakers suitable for music as well as speech, used to reinforce a

sound source, such as recorded music or a person giving a speech or distributing the

sound throughout a venue or building.

Simple PA systems are often used in small venues such as school auditoriums, churches,

and small bars. PA systems with many speakers are widely used to make announcements

in public, institutional and commercial buildings and locations. Intercom systems,

installed in many buildings, have microphones in many rooms allowing the occupants to

respond to announcements.

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Role of PA system in Human life safety

The PA system is capable of automatically managing an evacuation procedure by

providing instructions to occupants on what to do and where to go depending on their

location. By doing so, it will ensure the optimization of all fire escapes' capacity and avoid

congestion or crowding of fire escapes. In order to provide these, the fire alarm panel is

integrated to the system. This integration enables the system to determine which floors or

area is having an emergency and automatically conducts the evacuation process.

2.4 Telephone Exchange

The IR (Indian Railway) exchange network is a hierarchical architecture with 3 levels.

Highest level - Zonal Head Quarters (ZHQ) and Railway Board (RB)

Medium level - Divisional HQ (DHQ)

Lowest level - Important activity centers

All telephones shall be push button type. The signaling may be decadic or DTMF

Type. The telephones shall be of the following type:

- Ordinary

- Secretary and Executive type

- Digital

- Magneto

- 4 wire

The exchanges shall be interconnected using manual trunks through Trunk Operators

Or through Subscriber Trunk Dialing (STD) channels.

All exchange shall be available on IR STD network subjected to availability of

Channels. Each exchange shall have a distinct STD code. Alternate routing shall be

Provided as far as possible.

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Various components of the exchange system

a) Exchange hardware

b) Exchange software

c) Man Machine Interaction Terminal PC with Printer

d) Test and measuring instruments

e) Power supply Arrangement consisting of Batteries, Charger, Changeover panel and

stand-by system.

f) Intermediate Distribution Frame

g) Main Distribution Frame

h) Protection arrangement

i) Attendant consoles

j) Cable (underground and switch board)

k) Subscriber telephone set

l) Maintenance tools

m) Documentation

n) Lightning protection and earthling arrangement

The man machine language must be in English and user friendly. A VDU, keyboard

And a printer along with a PC must be available for interaction with the Exchange.

The exchange shall be worked with batteries on float. The capacity of the batteries

Shall be to provide minimum 8 hours back up. One set of battery, two chargers and a

Change over panel are to be provided for supplying power supply to exchange. The

Capacity of power supply arrangement shall be 30% higher than the exchange load.

The charger shall be preferably SMPS (Switch Mode Power Supply) type.

Intermediate Distribution Frame:

The IDF (Intermediate Distribution Frame) shall have disconnecting type connectors

With facility for isolating exchange indoor and outdoor side. The cable terminals shall

be installed on a rack. Protection arrangement shall be available on IDF. All testing

For line side shall be done from IDF. The IDF may be accommodated in exchange

Equipment room.

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Main Distribution Frame:

All outdoor cable shall be terminated on a rack forming the Main Distribution Frame

(MDF). This shall provide connectivity between outdoor cable and indoor switch

Board cable. The Main Distribution Frame shall be installed in a separate room but not

In the exchange room. An earth is connected across the frame for its entire length and

Preferably this shall be a copper strip clamped to the frame.

The outdoor cables shall be jelly filled underground type. The indoor cables shall be

Switch board cables. The outdoor cables shall be 20 pair, 50 pair and 100 pair

Capacity. The indoor cable shall be 5 pair, 10 pair, 20 pair and 50 pair. The outdoor

cable shall have outdoor Termination Box/Location Box with terminals

For proper termination of the cable. The indoor cable shall be terminated on CT boxes

Of appropriate size. The cables, cable Terminals in CT Boxes shall be planned with

30% spare capacity. All outdoor cable sheath shall be earthed while entering the

Exchange at MDF.

Lightning protection and Earthing arrangement:

The earthing arrangement shall be consisting of

- Earth pits minimum four with Earth electrodes connected in a ring

- Two earth wires connecting Earth Electrodes to Earth Distribution Frame

- Earth wires from each equipment to Earth Distribution Frame

(Exchange rack, IDF, MDF, Charger, Battery, Gen set, Power panel, Cables)

Electrical Supply:

230 V AC single phase shall be available. With power lines suitable for taking the

Load, Alternate supply shall be provided either traction supply or DG set. The power

Supply shall enter the room through MCB and changeover switch with proper earthling

Arrangement.

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2.5 Mobile Communication

Mobile Train Radio communication is a digital wireless network based on GSM-R

(Global System for Mobile Communication-Railway) designed on EIRENE (European

Integrated Railway Radio Enhanced Network) Functional requirement specification

(FRS) and System Requirement specification (SRS)

Basic features of GSM-R are

Point to Point call Allows user to make a distinct call.

Voice Broad cast call Allows groups of user to receive commonVoice Group call Allows groups of user to make calls withinEmergency call Allows user to call controller by short code orFunctional addressing Allows a user or an application to be reached

by means of a number, which identifies the

relevant function and not the physical terminal.Location dependent addressing Provides the routing of mobile originated calls

to

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Mobile communication process

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MSC

NITRAU

BSC

BTSS BTS BTS

BTS BTS

MOBILE

MOBILE

The system consists of following sub systems:

1. Mobile Station (MS)

2. Base Station Sub system (B SS)

3. Network and switching sub system (NSS) Operating sub system (OSS)

4. Dispatcher

5. Cab Radio

6. Power Supply Arrangement

The Radio link uses both FDMA (Frequency Division Multiple Access) and TDMA

(Time Division multiple Access). The 900 MHz frequency bands for down link and up

link signal are 935-960 MHz and 890-9 15 MHz respectively.

Frequency Used for GSM-R in Eastern Railway

Spot Frequencies

Uplink Dnli

nk

907.8 MHz 952.8 MHz908.0 MHz 953.0 MHz908.2 MHz 953.2 MHz908.4 MHz 953.4 MHz908.8 MHz 953.8 MHz909.0 MHz 954.2 MHz909.2 MHz 954.2 MHz

International Mobile Subscriber Identity (IMSI)– It is used to identify the called

MS. It is not known to the user and is used by network only. IMSI is stored in SIM, the

HLR and the serving VLR. The IMSI consists of three parts: A three digit Mobile

country Code (MCC), a two digit Mobile Network Code (MNC) and a Mobile Station

Identification Number (MSIN).

The directory number dialed to reach a mobile subscriber is called the mobile

subscriber ISDN (MSISDN) which is defined by the Numbering Plan. This number

includes a country code and a national destination code which identifies the

subscriber’s operator. It is stored in the HLR.

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Mobile Subscriber ISDN number:

MSISDN is a number uniquely identifying a subscription in a GSM or a UMTS mobile

network. Simply put, it is the telephone number to the SIM card in a mobile/cellular

phone. This abbreviation has several interpretations, the most common one being "Mobile

Subscriber Integrated Services Digital Network-Number".

The MSISDN together with IMSI are two important numbers used for identifying a

mobile subscriber. The latter identifies the SIM, i.e. the card inserted in to the mobile

phone, while the former is used for routing calls to the subscriber. IMSI is often used as a

key in the HLR ("subscriber database") and MSISDN is the number normally dialed to

connect a call to the mobile phone. A SIM is uniquely associated to an IMSI, while the

MSISDN can change in time (e.g. due to number portability), i.e. different MSISDNs can

be associated to the SIM.

Mobile Sub system (MS) :

The MS consists of two parts

Subscriber Identity Module (SIM)

Mobile Equipment (ME)

The SIM is removable and can be moved from one terminal to another. It is

authenticated via a personal Identity Number (PIN) between four to eight digit. This

PIN can be deactivated or changed by the user. If PIN is entered incorrectly in three

consecutive attempts, the phone is locked for all but emergency calls, until a PIN

unblocking key (PUK) is entered.

The SIM contains subscriber information and International Mobile Subscriber Identity

(IMSI).

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Power Supply:

The Mobile handset is equipped with power supply arrangement (Li-ion battery). It is a

maintenance free battery having detachable independent charger to recharge the battery

after discharge. Charging indication on ME screen shows the status of charging.

The Mobile handset can be dynamically registered and deregistered in the network for

different functional numbers as per requirement of the subscriber (ME) by keying from

the key pad in a programmed manner and monitoring the action in the display unit of ME.

Base Station Sub system (BSS) :

The BSS connects the MS and the NSS. The BSS contains of three parts.

Base transceiver Station (BTS).

Base Station Controller

Trans Coder Unit.

Base Trans receiver Station (BTS) :

The BTS performs channel coding/decryption. It contains transmitter and receivers,

antennas, the interface to the PCM facility and signaling equipment specific to the radio

interface in order to contact the MEs. It processes the signaling and speech required for

Mess in air interface at one side (via antenna) and with BSC in Abis interface (through

PCM 2Mb/s in OFC network) at the other side. The general architecture of the Base

station is based on the following modules:

The Compact Base Common Function (CBCF) performs all common functions such

as concentration, transmission, supervision and synchronization. A CBCF can be

dimensioned according to traffic.

The Power Amplifiers (PA) amplify the RF signal delivered to antenna through the

TX combiner. Each PA is physically independent unit, characterized by its

frequency band; output power can be controlled independently.

The Driver receiver units (DRX) amplify the RF signals (two, for diversity), process

the TDMA frames and drive the power amplifier. Each DRX is associated with one

RF channel, connected to the Frequency Hopping bus (FH bus) in order to allow

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base band hopping and packed as a physically independent unit. One TRX is then

made up of one PA and one DRX. Depending on frequency band, a specific DRX is

available to support EDGE (e-DRX).

The Transmission Combiners (TX combiners) combine the RF signals delivered by

several power Amplifiers and duplex them with the received signals. A variety of

coupling modules can be selected, depending on the type of combining (duplexer,

hybrid), the frequency band and the configuration (number of TRXs and antennas).

The reception multicouplers (LNAs + RX –splitters) pre-amplify and split the

received signal towards the DRX receivers. A variety of RX-splitters can be

selected, depending on the frequency band.

The Alarm module (RECALL) collects internal and external alarms. The number of

external alarms is up to 8.

Fan tray is kept at the bottom of the cabinet for keeping the module inside cabinet cool

by air circulation inside cabinet.

Power supply card to receive 48V DC supply from external source and to cater

required supplies to different active modules inside BTS cabinet.

CPCMI board on front panel inside BTS cabinets equipped with different LEDs to

indicate different status of the equipment.

System Specification:

Power Supply = - 48 V

DC.PA TX – Power = 30 W.Rx Sensitivity = -110

Power Supply: 48V/16 Amp. DC supply i48 V/16 As provided for the BTS cabinet.

Low Maintenance lead-acid battery with capacity 300AH with a Battery Charger

(230V AC/48V – 50 Amp. DC) shall be kept in float condition with load for this

purpose.

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Base Station Controller (BSC) :

In the BSS network, the BSC performs the tasks related to the BSS equipment

management & supervision and to the GSM call processing, mainly:

BTS supervision

Radio channel allocation

Radio channel Monitoring

Traffic management

TCU management

OMC-R link management

Handover procedures

Operation and maintenance request from the OMC-R processing

BSS configuration data and software storage

BSS performance counters management

Failure detection and processing

Trans coder unit (TCU):

The TCU carries out speech encoding/ decoding and rate adoption in data

transmission. It is designed to reduce the number of PCM links needed to convey radio

speech & Data channels between BTS, BSC & MSC. It enables code conversion of 16

Kbps channel from the BSC into 64 Kbps channels for MSC in both directions

Functional Overview:

It performs the following main tasks related to communication switching and

transcoding:

Switching: the TCU manages a time –division multiplexer connecting the BSC

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and MSC.

PCM link management: Using the configuration data provided by the BSC,

the TCU configures and monitors the PCM links on the A and after interfaces.

Transcoding and rate adaptation: Coding/decoding of the speech frames

and rate adaptation of data frames.

TCU equipment management: OA&M functions: initialization, startup, clock

synchronization from A-interface links, supervision, fault management,

software and configuration management.

Network and Switching Subsystem (NSS):

The NSS supports the switching functions, subscriber profiles and mobility

management. The basis switching function in the NSS is performed by the MSC. This

interface follows a signaling protocol used in the telephone network. The MSC also

communicates with other network elements external to GSM utilizing the same

signaling protocol. The current location of an MS is usually maintained by the HLR

( Home Location Register) and VLR (Visitor Location Register). When an MS moves

to the Home System to Visited system, its location is registered at the VLR of the

visited system. The VLR then informs the MS’s HLR of its current location. The

authentication center (AUC) is used in the Security data management for the

authentication of subscribers.

NSS &BSS installed in some sections of Indian Railways are of M/s Nortel or M/s

Siemens make.

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Data Bases

Home Location Register

(HLR)

Data base for management of mobile subscribers,

stores the IMSI, Mobile station ISDN number

(MSISDN) and current visitor location register

(VLR) address.

Keep track of the services associated with each MSVisitor location Register

(VLR)Catches some information from the HLR as

necessary for call control and service providing for

each mobile currently located in the geographical

area controlled by VLR connected to one MSC and isAuthentication center (AUC) A protected data base which has a copy of the secret

Key stored in each subscriber’s SIM card.

This Secret is used for authentication and encryption

Over the radio channel. Normally it is locate close toEquipment Identity ( EIR)

RegisterContains a list of all valid mobile station equipment

within the network, where each mobile station is

identified by its International Mobile Equipment

Power Consumption:

The average power consumption is 18W. If the device in the idle made, the maximum

power consumption is 3W i. e. dark display.

Power supply arrangement of GSM-R system:

MSC (D.C. Supply)

IN (A.C. supply)

OSS (OMC-R and OMC-S) (A.C. supply)

Dispatcher (A.C. Supply)

All the equipments are run by an uninterrupted (-) 48V DC supply and 230V AC

supply.

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2.6 FOIS

Freight Operations Information System (FOIS) was implemented in Indian Railways as an

initiative to leverage the use of Information Technology in the freight segment as an aid to

decision making and to ultimately improve the freight services. After successful

completion of trials and its implementation in Northern Railway, the system comprising

two modules- Rake Management System and Terminal Management System- was rolled

out to all the zones over Indian Railways. This was introduced, inter alia, to enhance the

accuracy and reliability of operating data to provide a real time view of transactions and to

serve as a decision making tool in allotment of rakes to customers and improved asset

turnaround.

Fig 5: System Architecture of FOIS

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The design conforms to the state of the art client server technology using middleware and

a Relational Data Base Management System (RDBMS). Application servers at the CRIS

are networked and linked to a central database for global level transactions. The central

database acts as the repository of all current and historical data. The application is

interface-ready for web-based services like connectivity to customers and e-payment

gateway interface.

Objectives of computerization

The objectives of computerization of freight operations included:

• enhancing the accuracy, reliability and timely availability of basic operating data

pertaining to events in the field locations;

• providing a wide range of information updated in ‘real time’ facilitating operating

management for better planning, direction and control of freight operations and revenue

accounting;

• Efficient scheduling and quick turnaround of rakes to enable effective and optimum

utilization of the assets and resources;

• facilitating acceptance of customers’ orders, billing and cash accounting of freight traffic

from identified nodal customer centers, which might not be the handling terminals; and

• Global tracking of consignments in real time and seamless availability of pipeline of

consignments for timely planning and just in time inventory management.

2.7 COIS

Indian Railways have taken up implementation of Coaching Operations Information

System (COIS) for a better management of punctuality, coaching stock management and

planning tools relating to time tabling and rake link optimization and to improve overall

efficiency of train services. 

Being developed by Centre for Railway Information System (CRIS), the Punctuality

Module seeks to provide terminals for installing in all control offices at the Divisions and

the Zonal Railway headquarters emergency control. The Zonal Railways have started the

daily train running data entry for testing and removing the software bugs. 

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Coaching Operations Information System (COIS): Captures events on Coaches/Rakes,

Generates Reports for Management of Coaching Stock. Data input predominantly at

Station/Coaching Yard level. Working on the system at station/yard level leads to

generation of required data (and memos for the operator).This works as input for MIS. All

station/yard activities from arrival to departure of rake are captured:

Yard stock entry

Dispute Resolve

Yard Position

Rake formation

Modify consist

Movement (Yard to yard)

Remove fit available coaches

Rake Examination

Search Feedbacks

Departure Reporting

Send Feedbacks

Generate memo

Arrival Reporting

2.8 INTERNET

Fig 6: OSI reference model

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The Internet is a worldwide network of computers and computer networks that can

communicate with each other using the Internet Protocol. Any computer on the Internet

has a unique IP address that can be used by other computers to route information to it.

Hence, any computer on the Internet can send a message to any other computer using its

IP address. These messages carry with them the originating computer's IP address

allowing for two-way communication. The Internet is thus an exchange of messages

between computers.

The Internet works in part because of protocols that govern how the computers and

routers communicate with each other. The nature of computer network communication

lends itself to a layered approach where individual protocols in the protocol stack run

more-or-less independently of other protocols. This allows lower-level protocols to be

customized for the network situation while not changing the way higher-level protocols

operate. Protocols are often talked about in terms of their place in the OSI reference

model (pictured on the right), which emerged in 1983 as the first step in an unsuccessful

attempt to build a universally adopted networking protocol suite. For the Internet, the

physical medium and data link protocol can vary several times as packets traverse the

globe. This is because the Internet places no constraints on what physical medium or data

link protocol is used. This leads to the adoption of media and protocols that best suit the

local network situation. In practice, most intercontinental communication will use

the Asynchronous Transfer Mode (ATM) protocol (or a modern equivalent) on top of

optic fibre. This is because for most intercontinental communication the Internet shares

the same infrastructure as the public switched telephone network.

LAN:

Despite the growth of the Internet, the characteristics of local area networks ("LANs" –

computer networks that do not extend beyond a few kilometers in size) remain distinct.

This is because networks on this scale do not require all the features associated with larger

networks and are often more cost-effective and efficient without them. When they are not

connected with the Internet, they also have the advantages of privacy and security.

However, purposefully lacking a direct connection to the Internet will not provide 100%

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protection of the LAN from hackers, military forces, or economic powers. These threats

exist if there are any methods for connecting remotely to the LAN.

WAN:

There are also independent wide area networks ("WANs" – private computer networks

that can and do extend for thousands of kilometers.) Once again, some of their advantages

include their privacy, security, and complete ignoring of any potential hackers – who

cannot "touch" them. Of course, prime users of private LANs and WANs include armed

forces and intelligence agencies that must keep their information completely secure and

secret.

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2.9 PRS

Reserved travel by Indian Railways is facilitated by the Passenger Reservation System

(PRS). PRS provides reservation services to nearly 1.5 to 2.2 million passengers a day on

over 2500 trains running throughout the country. The Indian Railways (IR) carries about

5.5 lakh passengers in reserved accommodation every day. The computerized Passenger

Reservation System (PRS) facilitates booking and cancelling of tickets from any of the

4000 terminals (i.e. PRS booking windows) all over the country. These tickets can be

booked or cancelled for journeys commencing in any part of India and ending in any other

part, with travel times as long as 72 hours and distances up to several thousand kilometers.

The PRS Application CONCERT (Country-wide Network of Computerized Enhanced

Reservation and Ticketing) is the world’s largest online reservation application, developed

and maintained by CRIS. The system currently operates from 5 Data centers. The server

clusters are connected together by a core network that enables universal terminals across

country, through which the travelling public can reserve a berth on any train, between any

pair of station for any date and class.

Fig 7: CONCERT Network Topology

The main modules of the PRS are the Reservation module, the Cancellation and

Modification Module, the Charting Module, the Accounting Module, and the Database

Module. The passengers’ request for reservation, cancellation and modification of journey

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are handled by the system through requisition slips. Major outputs generated by the system

are Reservationcum-journey tickets, Cancellation/Modification tickets, Reservation Charts

And Daily Terminal Cash Summary. The system is also capable of generating different

types of Management Information System Reports. The system was audited at ten zonal

railways namely Eastern Railway, Northern Railway, Southern Railway, Central Railway

(CR), Western Railway, South Central Railway, North Eastern Railway, South Eastern

Railway (SER), North East Frontier Railway (NFR) and East Central Railway (ECR).

2.10 Control system

Fig 8: Control Panel Room

The Control Organization of IR has primary responsibility for scheduling and running all trains,

and maintaining information on the positions and movements of all rolling stock. (These

functions are collectively known as control - an area of the railway network is said to be

'controlled' when a control office is in charge of it).A control chart is drawn up by the section

controller or his staff for each day. The chart plots distance along one axis (subdivided by block

sections, and showing stations, level crossings, etc., and time along the other.)The train’s path

are plotted on the chart to show the progress they are making; the slopes of the paths indicate the

speeds. Colours are used to mark out different categories of trains; eg: red for mail and express

trains, blue for ordinary passenger trains, and black for good trains. Crack or link goods trains

are indicated by special colours. If a train is stabled at a station, a horizontal red line is used to

denote that. Normally, at the end of a run on a section, the guard for a passenger train hands in

his report of timings and reasons for detentions along the way, so that they can be reconciled

with the control chart. Each division or district has a control office. In some divisions, this

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control office is in charge of all trains in the division or district. In other cases, in addition to the

headquarters control office there may be one or more outstation control offices which control

specific areas within the division. Each line is divided into a number of control sections for

convenience. Sometimes a line may be divided into more than one control section between yards

to account for very dense traffic, and lines with very light traffic may be combined together into

one control section. Each control section has a 'control board' which includes the telephony

equipment for the control staff to talk to any of the stations, block cabins, yards, loco sheds, in

the control section. A control section normally covers about 150-200km of a railway line.

3 Signaling

Signaling is one of the most important aspects of Railway communication. In the very early days

of the railways there was no fixed signaling to inform the driver of the situation of the line ahead.

Trains were driven “on sight”. But several unpleasant incidents accentuated the need for an

efficient signaling system. Earliest system involved the Time Interval technique. Here time

intervals were imposed between trains mostly around 10mins. But due to the frequent breakdown

of trains in those days this technique resulted in rear-end collisions. This gave rise to the fixed

signaling system wherein the track was divided into fixed sections and each section was

protected by a fixed signaling. This system is still being continued although changes have been

brought about in the basic signaling methods. Earlier mechanical signals were used but today

block signaling is through electric instruments. In the mid-19th century mechanical interlocking

was used. The purpose was to prevent the route for a train from being set up and its protecting

signal cleared if there

wasalready another conflicting route setup. The most modern development in signalinterlocking

is SSI- a means of controlling the safety requirements at junctions using electronic circuits which

replaced the relay systems supplied up to that time. In Indian Railways, first trial installation of

SSI was provided at Srirangam Station in 1987. Nowadays Track Circuits are used wherein the

current flow in the track circuit will be interrupted by the presence of wheels and a “stop” signal

will be shown. A “proceed” signal will be displayed if the current flows.

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3.1 Basic Signaling

The absolute block system is the most widespread method of train working on IR. The block

sections may be handled manually or automatically, or by some combination of those. Some

sections still use different forms of physical token systems such as the Neale's Ball Token

instruments.

Other than the block system some other special-purpose methods of train working are used in

some circumstances. There are many old and new kinds of signaling systems used by IR. Many

regions use lower-quadrant or upper-quadrant semaphore signaling (now with electric lamps for

night operation, but formerly using oil lamps). Many routes have been fitted with (automatic or

manual, 2-, 3- or 4-aspect) color-light signal systems that are electrically operated.

A few areas have seen the introduction of forms of centralized traffic control (CTC) in

conjunction with automatic colour-light signaling. (CTC was first introduced on the NER's busy

MG section between Gorakhpur and Chapra, and later on the Bongaigaon-Changsari section of

NFR.) The suburban section of Madras Egmore - Tambaram also has CTC.

Busy urban areas have electronic interconnections among the signal systems of the stations

within the areas. Suburban systems generally have colour-light signaling and automatic block

systems, sometimes with AWS or some form of automatic train stop systems (ATP, automatic

train protection) as well. Automatic train stop systems were tried on some main lines in the

1960's but were given up following excessive vandalism and pilferage of equipment and

maintenance problems.

Points and interlocking’s may be worked mechanically (rod or pipe linkages are common, but

earlier, double-wire systems were also used) or electrically (motor driven). Many points exist

which have to be manually operated at the location of the points after using a key to unlock the

points.

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Fig 9: Point Machines

Following British practice, IR's signalling is essentially route signalling where the signals

generally indicate which route has been set for a train, letting the driver choose the speed as

appropriate for the divergences, curves, etc. Of course no modern system of signalling is purely

route-based or speed-based, and there are elements of speed signalling in some of IR's signalling

as well.

3.2 Interlocking

In railway signalling, an interlocking is an arrangement of signal apparatus that prevents

conflicting movements through an arrangement of tracks such as junctions or crossings. The

signalling appliances and tracks are sometimes collectively referred to as an interlocking plant.

An interlocking is designed so that it is impossible to give clear signals to trains unless the route

to be used is proved to be safe.

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History of interlocking in India

Historically, before the advent of block instruments, access to sections of railway tracks was

done by the issuance of 'Line Clear' certificates by the station-masters of the stations to which the

sections belonged. The GIPR and EIR were in the forefront of mechanizing this process by

installing block instruments, semaphore signals, and interlocking. Paper Line Clear tickets are

still used in special circumstances and when communications have been disrupted. The adoption

of cabin interlocking progressed rapidly and by 1912 almost the entire Bombay-Delhi route was

equipped with it by the GIPR. Syke's Lock and Block systems were introduced on the BB&CI

Rly. And others starting in 1910 or so. Around this time track circuits and power signalling

(electric and electro-pneumatic) were also introduced for points and signals

These were used at major stations such as Bombay, Madras, and Calcutta. By 1931 more than

700 stations across India had interlocking. Lever frames from Tyer & Co., Westinghouse (60- or

70-lever frames were not uncommon) and others, and all-electric frames from Siemens (e.g., at

Madras Egmore and Madras Beach in 1935) were in use, as were many locally built lever frames

based on various British designs.

Mechanical Interlocking

Detector

A Detector is a very basic mechanical interlocking device that ensures that a signal can be pulled

off for a route only after the points have been set correctly for it. It also ensures that the tongue

rails for the points are positioned correctly (i.e., not warped to one side or another, for instance

because of being damaged in trail-throughs). The detector consists of a set of signal slides that

operate perpendicular to the blade connected to the points which determine the route. The blade

connected to the points has a number of notches, matching the number of signals. Each signal

slide has just one notch. The notch on the signal slide fits into the notch of the point blade only

when the points are correctly set for the route of the corresponding signal. When the signal slide

is positioned in this way, it frees the signal to be pulled off. Then when the signal is pulled off, it

moves the signal slide such that the points cannot be changed because the notch of the point

blade fouls the signal slide.

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Manually operated interlocking

This is a form of mechanical interlocking as well, but relies on the signalman to move about

from one set of points and signals to another carrying with him the keys used to operate them. At

small stations and on less busy branch lines various forms of manually operated mechanical

interlocking are still widespread.

Fig 10: Manually Operated Interlocking System

At points controlling catch sidings in hilly areas, often the interlocking is manual where the

driver has to use a key provided by the stationmaster or signalman of the last station before the

siding -- the key is inserted into the interlock box which notifies the signal cabin and the points

are then set for the main line and the signal is pulled off, giving the train authority to proceed.

(This system is common in many hilly areas, although busier lines with catch sidings are being

provided with automatically operating delayed signals where the points are controlled by a timer

and are set to the main line only after the train has halted for the prescribed period of time.)

3.3 PI and RRI

Panel Interlocking (PI) is the system used in most medium-sized stations on IR. In this, the

points and signals are worked by individual switches that control them.

Route Relay Interlocking (RRI) is the system used in large and busy stations that have to

handle high volumes of train movements. In this, an entire route through the station can be

selected and all the associated points and signals along the route can be set at once by a switch

for receiving, holding, blocking, or dispatching trains.

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Interlockings effected purely electrically (sometimes referred to as "all-electric") consist of

complex circuitry made up of relays in an arrangement of relay logic that ascertain the state or

position of each signal appliance. As appliances are operated, their change of position opens

some circuits that lock out other appliances that would conflict with the new position. Similarly,

other circuits are closed when the appliances they control become safe to operate. Equipment

used for railroad signalling tends to be expensive because of its specialized nature and fail-

safe design.

Interlocking operated solely by electrical circuitry may be operated locally or remotely with the

large mechanical levers of previous systems being replaced by buttons, switches or toggles on a

panel or video interface. Such an interlocking may also be designed to operate without a human

operator. These arrangements are termed automatic interlockings, and the approach of a train sets

its own route automatically, provided no conflicting movements are in progress.

Regardless of whether the mechanisms are controlled manually or by electronic circuits, and

whether they are operated mechanically or electrically, all interlocking schemes usually enforce

several or all of the following rules:

No signal can be pulled off unless corresponding points are set correctly.

Facing points are locked to the corresponding route when a signal is pulled off.

Signals for conflicting movements cannot be pulled off simultaneously.

Points for conflicting routes cannot be set simultaneously.

Trailing points are locked to the rear when a signal is pulled off.

Distants, warners, repeaters, etc. cannot be pulled off unless the corresponding stop signals are

pulled off.

Gate stop signals cannot be pulled off unless level-crossing gates are blocked to road traffic.

RRI and PI equipment is from Siemens and British manufacturers. In recent years interlocking

accomplished by modern integrated electronic circuitry instead of electromechanical relay

systems has come into use- Solid State Interlocking (‘SSI’). SSI is in place at 14 stations

inIndia.SSI equipment is manufactured by RDSO. 210 stations have RRI installations, and 1970

have Panel Interlocking. 247 stations now have RRI installations and the number of stations with

Panel Interlocking has risen to 2,426.

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3.3 EI

In the more advanced electrical or electronic interlocking schemes, the points and signals are

worked from one integrated mechanism in a signal cabin which features a display of the entire

track layout with indications of sections that are occupied, free, set for reception or dispatch, etc.

The interlocking is accomplished not by mechanical devices but by electrical circuitry -- relays

and switches in older electrical or electro pneumatic systems, and computerized circuits in the

newer electronic systems.

Electrical Interlocking

Electrical equipment of some kinds may be used even in the mechanical interlocking systems

described above (e.g., electrical relays that operate slotting). However, the basic operation there

remains mechanical in nature. In electrical interlocking, the fundamental mechanisms use

electric control extensively. Electrical interlocking often goes hand in hand with power signaling,

although there are or were installations with electrical interlocking provided for semaphore

signals.

Relays

Relays of various sorts are used to turn on or turn off circuits that control signals, points, slots,

level crossing gates, etc. Track relays are used for track circuits. Signal relays control signals.

Fig 11 : Indoor Relay Room

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Track Circuits

Track circuits are electrical circuits that are formed including the running rails. They are set up in

such a way that when a train is on the tracks that are part of the track circuit, the circuit is altered

in some way (usually, by current that normally flows in the track circuit being shunted through

the conductive body of the train), thereby activating a detector which may then be used, e.g., to

set signals at danger for the section.

Fig 12: Track Circuit

Track circuits help with interlocked operation as they allow signals to be pulled off only if the

section of track they control is safely clear of any vehicles. They also remove the human element

of needing to scrutinize the track for the presence of trains that may be out of view of the

signalling staff or cabin men. Track-circuiting is mandatory in sections where visibility is a

problem, shunting operations are routinely carried out on the block section outside station limits

on the main running line, or if special situations exist, e.g., if the advanced starter is more than

one full train-length ahead of the most advanced trailing points of the station.

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Axle Counters

Axle counters are devices that can count the number of axles of vehicles passing by them on the

track. Axle counters are installed at either end of the section of track of interest; when the

number of axles counted at entrance to the section is the same as the number of axles counted

exiting the section, it means the train has passed through the section intact. Axle counters are

used in some cases where track circuits are hard or impossible to operate (e.g., where metal

sleepers are provided, making track circuit operation impossible without re-installing the track,

or where conditions are such that there is too much electrical noise and conductivity problems

that make track circuits unworkable).

3.4 Centralized Traffic Control

Centralized traffic control (CTC) is a form of railway signalling that consolidates train routing

decisions that were previously carried out by local signal operators or the train crews themselves.

The system consists of a centralized train dispatcher's office that control. The system consists of

a centralized railroad interlocking and traffic flows in portions of the rail system designated as

CTC territory. One hallmark of CTC is a control panel with a graphical depiction of the railroad.

On this panel the dispatcher can keep track of trains' locations across the territory that the

dispatcher controls. Larger railroads may have multiple dispatchers’ offices and even multiple

dispatchers for each operating division. These offices are usually located near the

busiest yards or stations, and their operational qualities can be compared to air traffic towers.

Key to the concept of CTC is the notion of Traffic Control as it applies to railroads. Trains

moving in opposite directions on the same track cannot pass each other without special

infrastructure such as sidings and switches that allow one of the trains to move out of the way.

Initially the only two ways for trains to arrange such interactions was to somehow arrange it in

advance or provide a communications link between the authority for train movements (the

dispatcher) and the trains themselves. These two mechanisms for control would be formalized by

railroad companies in a set of procedures called Train order operation, which was later partly

automated through use of Automatic Block Signals (ABS). Signals in CTC territory are one of

two types: an absolute signal, which is directly controlled by the train dispatcher and helps Page | 39

design the limits of a control point, or an intermediate signal, which is automatically controlled

by the conditions of the track in that signal's block and by the condition of the following signal.

Train dispatchers cannot directly control intermediate signals and so are almost always excluded

from the dispatcher's control display except as an inert reference.

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Summary

Railways transport is an important and inexpensive mode for travel in India.

In order to meet Indian Railway’s demands for extreme reliability, many developments in the

area of signal and telecommunication have been done in order to provide the most technically-

effective solution.

Modern signalling systems using solid state interlocking auxiliary warning systems for

enhancing and ensuring safety, heavier rails, concrete sleepers, elastic fastenings, long span

bridges in pre-stressed concrete, improvements in overhead electric traction, use of information

technology in all area of railway working etc. are the other areas where Indian railways are

utilizing modern technology to meet the combined needs of traffic and safety. Still, there is a

great scope ahead for further improvements in the arena for efficient communications in the

railways on which engineers are pondering over for a better future in the Indian Railways.

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References

The following references have been helpful for preparation of this technical report along with the

guidance of our mentors and guides.

www.google.com

www.indianrailways.gov.in/railwayboard/.../telecom-man-idx.htm

Indian Railways-Wikipedia, the free encyclopedia

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