CHAPTER 1

INTRODUCTION INDIAN RAILWAYS

Fig. 1.1 Railway Logo

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INDIAN RAILWAYS 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.

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TypeDepartmental 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 & Bharatsinh Madhavsinh Solanki (Ministers of State)Vivek Sahai (Chairman, Railway Board)

ProductsRail transport, Cargo transport, Services, more...

Revenue88,355 crore (US$19.7

billion) (2009-10)

Net income9,595 crore (US$2.14

billion) (2009-10)

Owner(s) Republic of India (100%)

Employees 390,000 (2011)

Divisions 17 Railway Zones

Website Indianrailways.gov.in

Indian Railways has more than 64,215 kilometers 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, 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 narrow gauges. It also owns locomotive and coach production facilities.

1.1 RAILWAY ZONES

Indian Railways is divided into zones, which are further sub-divided into divisions. The

number of zones in Indian Railways increased from six to eight in 1951, nine in 1952, and

finally 17 in 2010. Each zonal railway is made up of a certain number of divisions, each

having a divisional headquarters. There are a total of sixty-seven divisions.

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Figure1.2 Railway Zones Map

The Delhi Metro is being built and operated by the Delhi Metro Rail Corporation Limited

(DMRC). The Government of India and the Government of Delhi jointly set up a company

called the Delhi Metro Rail Corporation (DMRC) on March 5, 1995 with E. Sreedharan as the

managing director .He is Padma Vibhushan awarded(Second highest honour) by Government

of India It is no way connected to Indian Railways.

Each of the seventeen zones, including Kolkata Metro, is headed by a General Manager (GM)

who reports directly to the Railway Board. The zones are further divided into divisions under

the control of Divisional Railway Managers (DRM). The divisional officers of engineering,

mechanical, electrical, signal and telecommunication, accounts, personnel, operating,

commercial and safety branches report to the respective Divisional Manager and are in charge

of operation and maintenance of assets. Further down the hierarchy tree are the Station

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Masters who control individual stations and the train movement through the track territory

under their stations' administration.

CHAPTER 2

SYSTEM OF SINALLING AND INTERLOCKING

2.1 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;

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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. Not all these methods require the use of physical signals and some

systems are specific to single track railways.

2.1.1. 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 time. This principle forms the basis of

most railway safety systems.

Figure 2.1 Block Signal

2.1.1.1. 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

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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 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.

2.1.1.2. 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.

2.1.1.3. 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.

2.1.1.4. FIXED BLOCK

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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.

2.1.1.5. 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.

2.2 TRAIN DETECTION

2.2.1 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

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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.

2.2.2 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.

2.3 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.

2.3.1 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 colour of the light. The driver therefore had to learn one set of indications for day

time viewing and another for night time viewing.

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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.

2.3.2 COLOUR 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.

Figure 2.2 Vertical Colour Light Signal

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.

On some railways, colour light signals display the same set of aspects as shown by the lights

on mechanical signals during darkness.

2.4. ROUTE SIGNALING AND SPEED SIGNALING

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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.

2.5 SAFETY SYSTEM

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.

2.6 INTERLOCKING

In the early days of the railways, signalmen were responsible for ensuring any points

(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.

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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..

2.6.1. 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 from operating 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.

2.6.1.1 CONTROL PANEL

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

interlocking.

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.

Figure 2.3 Control Panel

2.6.1.2.INDICATION PANEL

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).

Figure 2.4 RRI Panel

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

the corresponding indication on the indication panel.

2.6.1.3 POINTS

All the points in the yard except hand operated points are power operated and worked from th

RRI cabin by SM on duty. Motor operated points are numbered from 101 to 200. Hand

operated points are numbered from 201 to 250.

2.6.1.4 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.

2.6.1.5 POINT INDICATION:

Point indication on the indication panel, indicate the position 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 or occupied. 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.

The flashing of the individual point will continue till the failure is put right.

2.7. 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 travk 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, due to lamp

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

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CHAPTER 3

TRAIN TRAFFIC CONTROL

3.1. 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 varios way side stations,

important signal cabins, loco sheds, yard offices etc.

3.2. 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:

3.2.1 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.

3.2.2 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.

3.2.3 TRACTION LOCO CONTROL

Provided between traction loco controller and loco sheds, important station master’s

offices for optimum utilization of electric locomotives.

3.2.4 S&T CONTROL

Provided between test room and way stations for effective maintenance of s&t equipments.

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3.2.5 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.

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CHAPTER 4

COMMUNICATION SYATEM

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 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.

4.1 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

4.2 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.

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DRAWBACKS

Total interruption with any fault(cut water entered)

Theft

Joining is difficult

Equipment cost high.

Figure 4.1 Type of Transmission Singnal

4.2 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:

Figure 4.2 Microwave Receiver

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TRANSMISSION OF SIGNALS

GUIDED MEDIATRANSMISSION

OPTICAL FIBER

CO-AXIAL CABLE

UNGUIDED MEDIATRANSMISSION

MICROWAVETRANSMISSION

RADIOWAVETRANSMISSION

Waveguide & switching device

Radio

MultiplexerFrom

antenna

HF VF

The system modulation plans conforms to standard CCITT modulation plan. The standard

CCITT super groups one through 600 channel. 12 channel in 12 to 60khz frequency hand

make up the CCITT group A. Two additional channels are available between 4khz and 12khz.

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.

Figure 4.3 Flow Of Microwave Singnal

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CHAPTER5

MICROWAVE TRANSMISSION

5.1 INTRODUCTION

Radio communication involves :

The modulation of information (data to be sent) & generation of RF power tby the

radio transmitter.

Radiation of generated RF power into free space by transmitting antenna,

RF power transmitted in the form of electric waves to distant destination.

Reception of electro magnetic waves at destination by the receiving antenna.

The recovery of the information at the destination by the help of the radio receiver.

5.2 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.

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 lightthey can propagate in free space and vaccum.

Their behavior corresponds to light waves.

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5.3 MICROWAVES IN RAILWAY (MW)

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

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.

Figure 5.1 Microwave block Diagram

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CHAPTER 6

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

offer 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. The two books are the

introduction to fiber –optics by John Crisp and understanding fiber optics, Third edition by

Jeff Hecht.

Figure 6.1 Optical Fiber

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6.1 FIRST A BIT STORY

In 1870, John Tyndall demonstrated that Light travels the curve of a steam of water pouring

from a container, it was the simple principle that led to the study and development of

applications for this phenomenon. John Logie Baird patented a method of transmitting in a

glass rod for use in a early colour TV, but the optical looses inherent at the time made it

impractical to use. In the 1950’s more research and development into the transmission of

visible images through optical fiber led to some success in the medical world, as they began

using them in remote illumination and viewing instruments. In 1966 Charles Kao & George

Hockham proposed the transmission 0of information over glass fiber, and they also realized

that to make it a practical proposition, much lower losses in the cables were essential. This

was the driving force behind the developments to improve the optical losses in fiber,

manufacturing and today optical losses are significantly than the original target set out by

Charles Kao &George Hockham. he l

6.2 THE ADVANTAGES OF USING FIBRE OPTICS

Because of the low loss, high bandwidth properties of over fiber cable they can be used 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

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. Last but not least is the security aspect, it is very, very difficult to

tap into a fiber cable to read the data signals.

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Figure 6.2 Optical Fiber Internal Diagram

6.3 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

Over the years a variety of core sizes have been produced but these days there are only three

main sizes that are used in data communications, these are 50/125,62.5/125 and 8.3/125. The

50/125 and 62.5/125 micron multi-mode cables are the most widely used in the data networks,

although recently the 62.5 has become the more popular choice. This is rather unfortunate,

because the 50/125 has been found to be the better option for Gigabit Ethernet applications.

The 8.3/125 micron is a single mode cable which until now hasn’t been widely used in the

data networking, this was due to high cost of single mode hardware. Things are beginning to

change because the length limit for Gigabit Ethernet over 62.5/125 fiber has been reduced

around to 220m, and now, using 8.3/125 may be the only choice for campus size networks.

Hopefully , this shift to single mode may start to bring the cost down.

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6.4 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.

Figure 6.3 Single Mode & Multi Mode Fiber

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, however if you look straight down at the water you can see

the bottom of the pond. At some specific between these two view points the light stops

reflecting of the surface of water and passes through the air/water interface allowing you to

see the bottom of the pond. In multi-mode fiber as the name suggests, there are multiple –

modes of the propagation for the rays of the light.

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6.5 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 trough 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 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

Figure 6.4 Optical Fiber Communication Block Diagram

AVALANCHE PHOTO DIODE (APD) for optical to electrical conversion. Long lengths of cable

are joined by splicing the fiber.

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Modu-lator

D/A converter

De-modulator

A/D CONVERTER

Regenarator

Modu-lator

D/A converter

De-modulator

A/D CONVERTER

Regenarator

6.6 LIMITATIONS IN USING OPTICAL FIBRE CABLES

Difficulty in splicing (jointing).

Highly skilled staff would be required for maintenance.

Precision and costly instruments would be required.

Tapping is difficult. In railways difficulty for tap it for emergency and gate

communication.

Costly if underutilized.

Special interface equipment required for block working.

Accept unipolar codes i.e. return to codes only.

6.7 APPLICATION OF OPTICAL FIBRE COMMUNICATION IN RAILWAYS

Long haul circuits for administrative branch and data transmission circuits (PRS, FOIS

etc.).

Short haul circuits for linking of telephone exchanges.

Control communication

Signaling application for safe transmission.

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CHAPTER 7

PASSENGER RESERVATION SYSTEM (PRS)

7.1 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.

7.2 EQUIPMENTS

The equipment used in PRS are:

Modem

Multiplexing equipment

End terminal

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CHAPTER 8

UNRESERVED TICKETING SYSTEM (UTS)

8.1 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.

8.2 Equipment Overview

Block Diagram of UTS

Figure 8.1 Block Diagram Of UTS

The various equipment used are

Terminal and terminal server

Baseband modem

Router

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TerminalTerminal server

Terminal

Baseband modem

Router

RouterBaseband modem

Terminal server

PCM-TDM

Network

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 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.

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CHAPTER 9

INTERACTIVE VOICE RESPONSE SYSTEM (IVRS)

9.1 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”.

9.2 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.

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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.

Computer system.

Amplifier

Multiplexing equipment

Connecting wires and cables

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CHAPTER 10

RAILNET

10.1 INTRODUCTION

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.

10.3 WAN TECHNOLOGY

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

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 is shown on next page

I II

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III IV

V

Figure 10.1 Servers connectivity

EXAMPLE:-Puja express train no. is

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NEW DELHI

JAIPUR

MUMBAI

HAWRAH

SECUNDRABD

MADRAS

2304-DELHI to HAWRAH 2303-HAWRAH to DELHI

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.

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`10.4 Railway network

Figure 10.2 Railway Network

1. ETHERNET DATA >10MBPS

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PRS UTS

MODEM MODEM

MUX MUX

TERMINAL SERVER TS

SWITCH

ZONAL ROUTER NWR

ABUROAD

ALWARJAIPUR

DAUSA

2. SERIAL 3 WIRES (Transmitting. Receiving and Ground)

10.5 ETHERNET

tx+ tx- rx+ rx-

Figure 10.3 Two Wire Data Transmission

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.

10.6 TOUCH SCREEN

Y

GRID

x

Figure 10.4 Touch Screen

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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)

Figure10.5 Railway Passenger Process

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BEEP THE TICKET

CANCEL

CONFIRM

CANCEL

NON CANCELLATION

WAITING

INTERNET

IN QUEUE

WAITING

IVRS

TOUCH SCREEN

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.

CHAPTER 11

CONCLUSION & LEARNINGS

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It has been a honor to pursue my industrial training from the largest employer of the world,

the Indian Railways.

Railways uses one of the latest technologies that are available globally. So getting practical

training in railways gave me an golden opportunity to have an hands on experience of working

on those systems, although at some places we were not allowed to operate the real time

systems due to safety and other reasons but still I studied the systems and understood the

working.

At last to conclude I would like to add that the railways provided me an opportunity to get the

training on the finest technologies, and I sincerely want to express my gratitude towards

Indian railway employees, my college authorities my friends and family.

REFERENCES

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Web reference

1. www.indianrailway.gov.in 2. www.webrail.org 3. www.irfca.com

Mannuals & books

IROTP I9A

IROTP T6

IROTP F2A

IROTP GI9

IROTP GH7

IROTP RN2

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