The document provides an acknowledgement and thanks to various people who helped in the completion of an industrial training project at the EMU car shed in Ghaziabad, India. It discusses the turbo supercharger system used in locomotives including its components and working principles. It also describes the fuel oil system, including the fuel injection pump and nozzle. Key components of the bogie, air brake system, and speedometer are outlined. Failure analysis techniques and periodic overhauling processes are also mentioned.

1. ACKNOWLEDGEMENT
We take this opportunity to express our sincere gratitude to the peoples
who have been helpful in the successful completion of our industrial
training and this project. We would like to show our greatest appreciation
to the highly esteemed and devoted technical staff, supervisors of the
EMU car shed, Ghaziabad. We are highly indebted to them for their
tremendous support and help during the completion of our training and
project.
We are grateful to Mr. S.K. SINGH of EMU car shed, Ghaziabad and
Mr. N. GUPTA Principal of Training School who granted us the
permission of industrial training in the shed. We would like to thanks to
all those peoples who directly or indirectly helped and guided us to
complete our training and project in the shed, including the following
instructors and technical officers of EMU Training Centre and various
sections.
RAMESH KUMAR SHARMA
MECHANICAL ENGINEER ()

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Table of Contents
INTRODUCTION .......................................................................................................... 4
CTA (Chief Technical Assistance) CELL ................................................................................. 7
1. TURBO SUPERCHARGER .............................................................................................. 9
TURBO SUPERCHARGER AND ITS WORKING PRINCIPLE .................................................... 9
MAIN COMPONENTS OF TURBO-SUPERCHARGER .......................................................... 10
ROTOR ASSEMBLY .................................................................................................... 10
LUBRICATING, COOLING AND AIR CUSHIONING ................................................................. 11
LUBRICATING SYSTEM .................................................................................................. 11
COOLING SYSTEM ........................................................................................................ 11
AIR CUSHIONING ......................................................................................................... 11
2. FUEL OIL SYSTEM ................................................................................................................ 12
2.1 FUEL OIL SYSTEM.................................................................................................... 13
2.1.1 FUEL INJECTION PUMP ..................................................................................... 13
2.1.2 FUEL INJECTION NOZZLE ................................................................................... 15
2.2 CALIBRATION OF FUEL INJECTION PUMPS................................................................ 16
2.3 FUEL INJECTION NOZZLE TEST ................................................................................. 17
2.3.1 SPRAY PATTERN ............................................................................................... 17
2.3.2 SPRAY PRESSURE.............................................................................................. 18
2.3.3 DRIBBLING ....................................................................................................... 18
2.3.4 NOZZLE CHATTER ............................................................................................. 18
2. BOGIE ............................................................................................................................. 19
3.1 Key Components of a Bogie ........................................................................................ 19
3.2 CLASSIFICATION OF BOGIE ...................................................................................... 20
3.3 Failure and remedies in the bogie section:-.................................................................. 21
4. AIR BRAKES ......................................................................................................................... 21
AIR BRAKE SYSTEM OPERATION........................................................................................ 22
LAYOUT:-..................................................................................................................... 23
4.1VALVES ................................................................................................................... 24
4.1.1 A-9 Valve............................................................................................................. 24

3. 4.1.2 SA-9 Valve ........................................................................................................... 24
4.1.3 MU 2B VALVE ...................................................................................................... 24
D-1 Emergency brake valve .......................................................................................... 25
5. SPEEDOMETER .................................................................................................................... 26
WORKING MECHANISM ................................................................................................... 26
Salient features ............................................................................................................... 27
Applications .................................................................................................................... 27
Technical Specifications .............................................................................................. 28
A. Operating conditions................................................................................................ 28
B. Analogue indication ................................................................................................ 28
C. Digital indication .................................................................................................... 29
D. General ................................................................................................................... 29
6. PIT WHEEL LATHE ................................................................................................................ 29
6.1 Wheel turning ............................................................................................................ 30
CAUSES OF WHEEL SKIDDING- ...................................................................................... 30
7. FAILURE ANALYSIS ............................................................................................................... 31
7.1 Metallurgical lab. ....................................................................................................... 32
7.2 Swelling test .............................................................................................................. 32
Procedure: .................................................................................................................. 32
Rubber used in car : ......................................................................................................... 33
7.3 ULTRASONIC TESTING................................................................................................. 33
7.4 ZYGLO TEST ............................................................................................................... 34
7.5 RED DYE PENETRATION TEST (RDP) ............................................................................ 34
Principles ................................................................................................................... 34
8. SCHEDULE EXAMINATION .................................................................................................... 35
9. PERIODIC OVERHOULING ..................................................................................................... 36
REFERENCES: .......................................................................................................................... 40
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INDIAN RAILWAY HISTORY
INTRODUCTION

5. Indian Railways is the state-owned railway company of India. It comes under
the Ministry of Railways. Indian Railways has one of the largest and busiest rail
networks in the world, transporting over 18 million passengers and more than
2 million tonnes of freight daily. Its revenue is Rs.107.66 billion. It is the world's
largest commercial employer, with more than 1.4 million employees. It
operates rail transport on 6,909 stations over a total route length of more than
63,327 kilometers(39,350 miles).The fleet of Indian railway includes over
200,000 (freight) wagons, 50,000 coaches and 8,000 locomotives. It also owns
locomotive and coach production facilities. It was founded in 1853 under the
East India Company.
Indian Railways is administered by the Railway Board. Indian Railways is
divided into 16 zones. Each zone railway is made up of a certain number of
divisions. There are a total of sixty-seven divisions. It also operates the Kolkata
metro. There are six manufacturing plants of the Indian Railways. The total
length of track used by Indian Railways is about 108,805 km (67,608 mi) while
the total route length of the network is 63,465 km (39,435 mi). About 40% of
the total track kilometres is electrified & almost all electrified sections use
25,000 V AC. Indian railways uses four rail track gauges|~|
1. The broad gauge (1670 mm)
2. The meter gauge (1000 mm)
3. Narrow gauge (762 mm)
4. Narrow gauge (610 mm).
Indian Railways operates about 9,000 passenger trains and transports 18
million passengers daily .Indian Railways makes 70% of its revenues and most
of its profits from the freight sector, and uses these profits to cross-subsidies
the loss-making passenger sector.
CLASSIFICATION
1. Standard “Gauge” designations and dimensions:-
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 W = Broad gauge (1.67 m)

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 Y = Medium gauge ( 1 m)
 Z = Narrow gauge ( 0.762 m)
 N = Narrow gauge ( 0.610 m)
2. “ Type of Traction” designations:-
 D = Diesel-electric traction
 C = DC traction
 A = AC traction
 CA=Dual power AC/DC traction
3. The “ type of load” or “Service” designations:-
 M= Mixed service
 P = Passenger
 G= Goods
 S = Shunting
4. “ Horse power ” designations from June 2002 (except WDP-1 & WDM-2
LOCOS)
 ‘ 3 ’ For 3000 horsepower
 ‘ 4 ’ For 4000 horsepower
 ‘ 5 ’ For 5000 horsepower
 ‘ A ’ For extra 100 horsepower
 ‘B’ For extra 200 horsepower and so on.
Hence ‘WDM-3A’ indicates a broad gauge loco with diesel-electric traction. It
is for mixed services and has 3100 horsepower.|~|
EMU CAR SHED, GHAZIABAD
EMU CAR SHED is an industrial-technical setup, where repair and
maintenance works of electric locomotives is carried out, so as to keep
the loco working properly. It contributes to increase the operational life
of electric locomotives and tries to minimize the line failures. The
technical manpower of a shed also increases the efficiency of the loco
and remedies the failures of loco.
The shed consists of the infrastructure to berth, dismantle, repair and test the
loco and subsystems. The shed working is heavily based on the manual
methods of doing the maintenance job and very less automation processes are
used in sheds, especially in India.

7. The EMU shed usually has:-
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 Berths and platforms for loco maintenance.
 Pits for under frame maintenance
 Heavy lift cranes and lifting jacks
 Fuel storage and lube oil storage, water treatment plant and
testing labs etc.
 Sub-assembly overhauling and repairing sections
 Machine shop and welding facilities.
EMU shed of Northern Railway is located in GHAZIABAD. The shed was
established in 1982. It was initially planned to home 75 locomotives. The shed
cater the needs of Northern railway. This shed mainly provides locomotive to
run the mail, goods and passenger services. No doubt the reliability, safety
through preventive and predictive maintenance is high priority of the shed. To
meet out the quality standard shed has taken various steps and obtaining of
the ISO-9001-2008 IRQS CERTIFICATION is among of them. The EMU Shed is
equipped with modern machines and plant required for Maintenance of Diesel
Locomotives and has an attached store depot. To provide pollution free
atmosphere, EMU Shed has constructed Effluent Treatment Plant. The morale
of supervisors and staff of the shed is very high and whole shed works like a
well-knit team.
CTA (Chief Technical Assistance) CELL
This cell performs the following functions:-
 Failure analysis of EMU locos
 Finding the causes of sub system failures and material failures
 Formation of inquiry panels of Mechanical and Electrical
engineers and to help the special inquiry teams
 Material failures complains, warnings and replacement of stock
communications with the component manufacturers
 Issues the preventive instructions to the technical workers and
engineers

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 Preparation of full detailed failure reports of each loco and sub
systems, components after detailed analysis.

9. 1. TURBO SUPERCHARGER
The diesel engine produces mechanical energy by converting heat energy
derived from burning of fuel inside the cylinder. For efficient burning of fuel,
availability of sufficient air in proper ratio is a prerequisite.
In a naturally aspirated engine, during the suction stroke, air is being sucked
into the cylinder from the atmosphere. The volume of air thus drawn into the
cylinder through restricted inlet valve passage, within a limited time would also
be limited and at a pressure slightly less than the atmosphere. The availability
of less quantity of air of low density inside the cylinder would limit the scope of
burning of fuel. Hence mechanical power produced in the cylinder is also
limited. An improvement in the naturally aspirated engines is the super-charged
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or pressure charged engines.
A turbocharger, or turbo, is a gas compressors used for forced-induction of an
internal combustion engine. Like a supercharger, the purpose of a
turbocharger is to increase the density of air entering the engine to create
more power. However, a turbocharger differs in that the compressor is
powered by a turbine driven by the engine's own exhaust gases.
TURBO SUPERCHARGER AND ITS WORKING PRINCIPLE
The exhaust gas discharge from all the cylinders accumulate in the
common exhaust manifold at the end of which, turbo- supercharger is fitted.
The gas under pressure there after enters the turbo- supercharger through the
torpedo shaped bell mouth connector and then passes through the fixed

10. nozzle ring. Then it is directed on the turbine blades at increased pressure and
at the most suitable angle to achieve rotary motion of the turbine at maximum
efficiency. After rotating the turbine, the exhaust gas goes out to the
atmosphere through the exhaust chimney. The turbine has a centrifugal
blower mounted at the other end of the same shaft and the rotation of the
turbine drives the blower at the same speed. The blower connected to the
atmosphere through a set of oil bath filters, sucks air from atmosphere, and
delivers at higher velocity. The air then passes through the diffuser inside the
turbo- supercharger, where the velocity is diffused to increase the pressure of
air before it is delivered from the turbo- supercharger.
MAIN COMPONENTS OF TURBO-SUPERCHARGER
Turbo- supercharger consists of following main components.
 Gas inlet casing.
 Turbine casing.
 Intermediate casing
 Blower casing with diffuser
 Rotor assembly with turbine and rotor on the same shaft.
ROTOR ASSEMBLY
The rotor assembly consists of rotor shaft, rotor blades, thrust collar,
impeller, inducer, centre studs, nosepiece, locknut etc. assembled together.
The rotor blades are fitted into fir tree slots, and locked by tab lock washers.
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11. This is a dynamically balanced component, as this has a very high rotational
speed.
LUBRICATING, COOLING AND AIR CUSHIONING
LUBRICATING SYSTEM
One branch line from the lubricating system of the engine is connected to
the turbo- supercharger. Oil from the lube oils system circulated through the
turbo- supercharger for lubrication of its bearings. After the lubrication is over,
the oil returns back to the lube oil system through a return pipe. Oil seals are
provided on both the turbine and blower ends of the bearings to prevent oil
leakage to the blower or the turbine housing.
COOLING SYSTEM
The cooling system is integral to the water cooling system of the engine.
Circulation of water takes place through the intermediate casing and the
turbine casing, which are in contact with hot exhaust gases. The cooling water
after being circulated through the turbo- supercharger returns back again to
the cooling system of the locomotive.
AIR CUSHIONING
There is an arrangement for air cushioning between the rotor disc and the
intermediate casing face to reduce thrust load on the thrust face of the bearing
which also solve the following purposes.
 It prevents hot gases from coming in contact with the lube oil.
 It prevents leakage of lube oil through oil seals.
 It cools the hot turbine disc.
Fitments of higher capacity Turbo Supercharger- following new
generation Turbo Superchargers have been identified by EMU car shed for
2600/3100HP diesel engine and tabulated in table 1.
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12. TABLE 1
TYPE POWER COOLING
1.ALCO 2600HP Water cooled
2.ABB TPL61 3100HP Air cooled
3.HISPANO SUIZA HS 5800 NG 3100HP Air cooled
4. GE 7S1716 3100HP Water cooled
5. NAPIER NA-295 2300,2600&3100HP Water cooled
6. ABB VTC 304 2300,2600&3100HP Water cooled
2. FUEL OIL SYSTEM
All locomotive have individual fuel oil system. The fuel oil system is
designed to introduce fuel oil into the engine cylinders at the correct time, at
correct pressure, at correct quantity and correctly atomised. The system injects
into the cylinder correctly metered amount of fuel in highly atomised form.
High pressure of fuel is required to lift the nozzle valve and for better
penetration of fuel into the combustion chamber. High pressure also helps in
proper atomisation so that the small droplets come in better contact with the
compressed air in the combustion chamber, resulting in better combustion.
Metering of fuel quantity is important because the locomotive engine is a
variable speed and variable load engine with variable requirement of fuel.
Time of fuel injection is also important for better combustion.
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13. 2.1 FUEL OIL SYSTEM
The fuel oil system consists of two integrated systems. These are-
 FUEL INJECTION PUMP (F.I.P).
 FUEL INJECTION SYSTEM.
2.1.1 FUEL INJECTION PUMP
It is a constant stroke plunger type pump with variable quantity of fuel
delivery to suit the demands of the engine. The fuel cam controls the pumping
stroke of the plunger. The length of the stroke of the plunger and the time of
the stroke is dependent on the cam angle and cam profile, and the plunger
spring controls the return stroke of the plunger. The plunger moves inside the
barrel, which has very close tolerances with the plunger. When the plunger
reaches to the BDC, spill ports in the barrel, which are connected to the fuel
feed system, open up. Oil then fills up the empty space inside the barrel. At the
correct time in the diesel cycle, the fuel cam pushes the plunger forward, and
the moving plunger covers the spill ports. Thus, the oil trapped in the barrel is
forced out through the delivery valve to be injected into the combustion
chamber through the injection nozzle. The plunger has two identical helical
grooves or helix cut at the top edge with the relief slot. At the bottom of the
plunger, there is a lug to fit into the slot of the control sleeve. When the
rotation of the engine moves the camshaft, the fuel cam moves the plunger to
make the upward stroke.
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14. It may also rotate slightly, if necessary through the engine governor, control
shaft, control rack, and control sleeve. This rotary movement of the plunger
along with reciprocating stroke changes the position of the helical relief in
respect to the spill port and oil, instead of being delivered through the pump
outlet, escapes back to the low pressure feed system. The governor for engine
speed control, on sensing the requirement of fuel, controls the rotary motion
of the plunger, while it also has reciprocating pumping strokes. Thus, the
alignment of helix relief with the spill ports will determine the effectiveness of
the stroke. If the helix is constantly in alignment with the spill ports, it bypasses
the entire amount of oil, and nothing is delivered by the pump.
The engine stops because of no fuel injected, and this is known as ‘NO-FUEL’
position. When alignment of helix relief with spill port is delayed, it
results in a partly effective stroke and engine runs at low speed and power
output is not the maximum. When the helix is not in alignment with the spill
port through out the stroke, this is known as ‘FULL FUEL POSITION’, because
the entire stroke is effective.
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15. Oil is then passed through the delivery valve, which is spring loaded. It opens
at the oil pressure developed by the pump plunger. This helps in increasing the
delivery pressure of oil. it functions as a non-return valve, retaining oil in the
high pressure line. This also helps in snap termination of fuel injection, to
arrest the tendency of dribbling during the fuel injection. The specially
designed delivery valve opens up due to the pressure built up by the pumping
stroke of plunger. When the oil pressure drops inside the barrel, the landing on
the valve moves backward to increase the space available in the high-pressure
line. Thus, the pressure inside the high-pressure line collapses, helping in snap
termination of fuel injection. This reduces the chances of dribbling at the
beginning or end of fuel injection through the fuel injection nozzles.
2.1.2 FUEL INJECTION NOZZLE
The fuel injection nozzle or the fuel injector is fitted in the cylinder head
with its tip projected inside the combustion chamber. It remains connected to
the respective fuel injection pump with a steel tube known as fuel high
pressure line. The fuel injection nozzle is of multi-hole needle valve type
operating against spring tension. The needle valve closes the oil holes by
blocking the oil holes due to spring pressure. Proper angle on the valve and the
valve seat, and perfect bearing ensures proper closing of the valve.
Due to the delivery stroke of the fuel injection pump, pressure of fuel oil in the
fuel duct and the pressure chamber inside the nozzle increases. When the
pressure of oil is higher than the valve spring pressure, valve moves away from
its seat, which uncovers the small holes in the nozzle tip. High-pressure oil is
then injected into the combustion chamber through these holes in a highly
atomised form. Due to injection, hydraulic pressure drops, and the valve
returns back to its seat terminating the fuel injection, termination of fuel
injection may also be due to the bypassing of fuel injection through the helix in
the fuel injection pump causing a sudden drop in pressure.
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16. 2.2 CALIBRATION OF FUEL INJECTION PUMPS
Each fuel injection pump is subject to test and calibration after repair or
overhaul to ensure that they deliver the same and stipulated amount of fuel at
a particular rack position. Every pump must deliver regulated and equal
quantity of fuel at the same time so that the engine output is optimum and at
the same time running is smooth with minimum vibration.
The calibration and testing of fuel pumps are done on a specially designed
machine. The machine has a 5 HP reversible motor to drive a cam shaft
through V belt. The blended test oil of recommended viscosity under
controlled temperature is circulated through a pump at a specified pressure
for feeding the pump under test. It is very much necessary to follow the laid
down standard procedure of testing to obtain standard test results. The pump
under test is fixed on top of the cam box and its rack set at a particular position
to find out the quantum of fuel delivery at that position. The machine is then
switched on and the cam starts making delivery strokes. A revolution counter
attached to it is set to trip at 500 RPM or 100 RPM as required. With the cam
making strokes, if the pump delivers any oil, it returns back to the reservoir in
normal state. A manually operated solenoid switch is switched on and the oil
is diverted to a measure glass till 300 strokes are completed after operation of
the solenoid switch. Thus the oil discharged at 300 working strokes of the
pump is measured which should normally be within the stipulated limit. The
purpose of measuring the output in 300 strokes is to take an average to avoid
errors. The pump is tested at idling and full fuel positions to make sure that
they deliver the correct amount of fuel for maintaining the idling speed and so
also deliver full HP at full load. A counter check of the result at idling is done
on the reverse position of the motor which simulates slow running of the
engine.
If the test results are not within the stipulated limits as indicated by the
makers then adjustment of the fuel rack position may be required by moving
the rack pointer, by addition or removal of shims behind it. The thickness of
shims used should be punched on the pump body. The adjustment of rack is
done at the full fuel position to ensure that the engine would deliver full horse
power. Once the adjustment is done at full fuel position other adjustment
should come automatically. In the event of inconsistency in results between
full fuel and idling fuel, it may call for change of plunger and barrel assembly.
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17. The calibration value of fuel injection pump as supplied by the makers is
tabulated in table 2 at 300 working strokes, rpm -500, temp.-100 to 120 0F &
pressure 40 PSI:
Table 2
Dia.of element(mm) Rack(mm) Required volume of
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fuel(cc)
15 mm 30 mm(full load)
9 mm(Idling)
351 cc +5/-10
34 cc +1/-5
17 mm 28 mm (full load)
9 mm (Idling)
401 cc +4/-11
45 cc +1/-5
Errors are likely to develop on the calibration machine in course of time and
it is necessary to check the machine at times with master pumps supplied by
the makers. These pumps are perfectly calibrated and meant for use as
reference to test the calibration machine itself. Two master pumps, one for
full fuel and the other for idling fuel are there and they have to be very
carefully preserved only for the said purpose.
2.3 FUEL INJECTION NOZZLE TEST
The criteria of a good nozzle are good atomization, correct spray pattern and
no leakage or dribbling. Before a nozzle is put to test the assembly must be
rinsed in fuel oil, nozzle holes cleaned with wire brush and spray holes cleaned
with steel wire of correct thickness.
The fuel injection nozzles are tested on a specially designed test stand,
where the following tests are conducted.
2.3.1 SPRAY PATTERN
Spray of fuel should take place through all the holes uniformly and properly
atomized. While the atomization can be seen through the glass jar, an
impression taken on a sheet of blotting paper at a distance of 1 to 1 1/2 inch
also gives a clear impression of the spray pattern.

18. 2.3.2 SPRAY PRESSURE
The stipulated correct pressure at which the spray should take place 3900-
4050 psi for new and 3700-3800 psi for reconditioned nozzles. If the pressure
is down to 3600 psi the nozzle needs replacement. The spray pressure is
indicated in the gauge provided in the test machine. Shims are being used to
increase or decrease the tension of nozzle spring which increases or
decreases the spray pressure
2.3.3 DRIBBLING
There should be no loose drops of fuel coming out of the nozzle before or
after the injections. In fact the nozzle tip of a good nozzle should always
remain dry. The process of checking dribbling during testing is by having
injections manually done couple of times quickly and checks the nozzle tip
whether leaky.
Raising the pressure within 100 psi of set injection pressure and holding it for
about 10 seconds may also give a clear idea of the leakage.
The reasons of nozzle dribbling are
1. Improper pressure setting
2. Dirt stuck up between the valve and the valve seat
3. Improper contact between the valve and valve seat
4. Valve sticking inside the valve body.
2.3.4 NOZZLE CHATTER
The chattering sound is a sort of cracking noise created due to free
movement of the nozzle valve inside the valve body. If it is not proper then
chances are that the valve is not moving freely inside the nozzle.
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19. 2. BOGIE
A bogie is a wheeled wagon or trolley. In mechanics terms, a bogie is a
chassis or framework carrying wheels, attached to a vehicle. It can be
fixed in place, as on a cargo truck, mounted on a swivel, as on a railway
carriage or locomotive, or sprung as in the suspension of a caterpillar
tracked vehicle. Bogies serve a number of purposes:-
 To support the rail vehicle body
 To run stably on both straight and curved track
 To ensure ride comfort by absorbing vibration, and minimizing centrifugal
forces when the train runs on curves at high speed.
 To minimize generation of track irregularities and rail abrasion.
Usually two bogies are fitted to each carriage, wagon or locomotive, one at
each end.
3.1 Key Components of a Bogie
 The bogie frame itself.
 Suspension to absorb shocks between the bogie frame and the rail vehicle
body. Common types are coil springs, or rubber airbags.
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20.  At least two wheel set, composed of axle with a bearings and wheel at each
end.
 Axle box suspension to absorb shocks between the axle bearings and the
bogie frame. The axle box suspension usually consists of a spring between
the bogie frame and axle bearings to permit up and down movement, and
sliders to prevent lateral movement. A more modern design uses solid
rubber springs.
 Brake equipment:-Brake shoes are used that are pressed against the tread
of the wheels.
 Traction motors for transmission on each axle.
3.2 CLASSIFICATION OF BOGIE
Bogie is classified into the various types described below according to their
configuration in terms of the number of axle, and the design and structure of
the suspension. According to UIC classification two types of bogie in Indian Railway
are:-
1. Bo-Bo
2. Co-Co
A Bo-Bo is a locomotive with two independent four-wheeled bogies with all
axles powered by individual traction motors. Bo-Bos are mostly suited to
express passenger or medium-sized locomotives.
A Co-Co is a code for a locomotive wheel arrangement with two six-wheeled
bogies with all axles powered, with a separate motor per axle. Co-Cos is most
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21. suited to freight work as the extra wheels give them good adhesion. They are
also popular because the greater number of axles results in a lower axle load .
3.3 Failure and remedies in the bogie section:-
 Breakage of coiled springs due to heavy shocks or more weight or defective
material. They are tested time to time to check the compression limit.
Broken springs are replaced.
 14 to 60 thou clearance is maintained between the axle and suspension
bearing. Lateral clearance is maintained between 60 to 312 thou. Less
clearance will burn the oil and will cause the seizure of axle. Condemned
parts are replaced.
 RDP tests are done on the frame parts, welded parts, corners, guide links
and rigid structures of bogie and minor cracks can be repaired by welding.
 Axle suspension bearings may seizure due to oil leakage, cracks etc. If axle
box bearing’s roller is damaged then replaced it completely.
4. AIR BRAKES
An air brake is a conveyance braking system actuated by compressed air.
Modern trains rely upon a fail preventive air brake system that is based upon a
design patented by George Westinghouse on March 5,1872. In the air brake's
simplest form, called the straight air system, compressed air pushes on a
piston in a cylinder. The piston is connected through mechanical linkage to
brake shoes that can rub on the train wheels, using the resulting friction to
slow the train.
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22. AIR BRAKE SYSTEM OPERATION
The compressor in the locomotive produces the air supplied to the system.
It is stored in the main reservoir. Regulated pressure of 6 kg/cm2 flows to the
feed pipe through feed valve and 5-kg/cm2 pressure by driver’s brake valve to
the brake pipe. The feed pipe through check valve charges air reservoir via
isolating cock and also by brake pipe through distributor valve. The brake pipe
pressure controls the distributor valves of all the coaches/wagons which in
turn control the flow of compressed air from Air reservoir to break cylinder in
application and from brake cylinder to atmosphere in release.
During application, the driver in the loco lowers the BP pressure. This brake
pipe pressure reduction causes opening of brake cylinder inlet passage and
simultaneously closing of brake cylinder outlet passage of the distributor valve.
In this situation, auxiliary reservoir supplies air to brake cylinder. At application
time, pressure in the brake cylinder and other brake characteristics are
controlled by distributor valve.
During release, the BP pressure is raised to 5 kg/cm2 . This brake pipe pressure
causes closing of brake cylinder inlet passage and simultaneously opening of
brake cylinder outlet passage of the distributor valve.
The distributor valve connects brake cylinder to atmosphere. The brake
cylinder pressure can be raised or lowered in steps.
In case of application by alarm chain pulling, the passenger emergency alarm
signal device (PEASD) is operated which in turn actuates passenger valve (PEV)
causing exhaust of BP pressure through a choke of 4 mm. Opening of guard
emergency brake valve also makes emergency brake application.
There are two case of braking, when only loco move and when entire train
move. Consequently there are two valves in the driver cabin viz SA-9&A-9.
Braking operation of above case is shown in chart below.
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23. LAYOUT:-
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PEV
DC
DV
CR AR
BC BC
DC
Guard
emergency
brake
system
PEASD PEASD
FP
BP
GEBV
Pressure
gauge
Cut off
angle cock
Passenger alarm
system
Core
brake
system

24. 4.1VALVES
4.1.1 A-9 Valve
The A-9 Automatic Brake Valve is a compact self lapping, pressure
maintaining Brake Valve which is capable of graduating the application or
release of locomotive and train brakes. A-9 Automatic Brake Valve has five
positions: Release, minimum Reduction, Full Service, Over Reduction and
Emergency.
4.1.2 SA-9 Valve
SA-9 Independent Brake Valve is a compact self lapping, pressure
maintaining Brake Valve which is capable of graduating the application or
release of Locomotive Air Brakes independent of Automatic Brake. The SA-9
Independent Brake Valve is also capable of releasing an automatic brake
application on the Locomotive without affecting the train brake application.
The SA-9 Brake Valve has three positions : quick release, release and
application.
4.1.3 MU 2B VALVE
The MU-2B Valve is a manually operated, two positions and multiple
operated valve arranged with a pipe bracket and is normally used for
locomotive brake equipment for multiple unit service between locomotives
equipped with similar system in conjunction with F-1 Selector Valve.
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25. D-1 Emergency brake valve
The D-1 Emergency Brake Valve is a manually operated device
Which provides a means of initiating an emergency brake application.
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26. 5. SPEEDOMETER
The electronic speedometer is intended to measure traveling speed and to
record the status of selected locomotive engine parameters every second. It
comprises a central processing unit that performs the basic functions, two
monitors that are used for displaying the measured speed values and entering
locomotive driver’s identification data and drive parameters and a speed
transducer. The speedometer can be fitted into any of railway traction
vehicles.
WORKING MECHANISM
Speedometer is a closed loop system in which opto-electronic pulse
generator is used to convert the speed of locomotive wheel into the
corresponding pulses. Pulses thus generated are then converted into the
corresponding steps for stepper motor. These steps then decide the
movement of stepper motor which rotates the pointer up to the desired
position. A feed back potentiometer is also used with pointer that provides a
signal corresponding to actual position of the pointer, which then compared
with the step of stepper motor by measuring and control section. If any error is
observed, it corrected by moving the pointer to corresponding position.
Presently a new version of speed-time-distance recorder cum indicator unit
TELPRO is used in the most of the locomotive. Features and other technical
specification of this speedometer are given below.
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27. Salient features
5. Light weight and compact in size
6. Adequate journey data recording capacity
7. Both analog and digital displays for speed
8. Both internal and external memories for data storage
9. Memory freeze facility
10.Stepless wheel wear compensation
11.Dual sensor opto electronic pulse generator for speed sensing
12.Over speed audio visual alarm
13.User friendly Windows-based data extraction and analysis software
14.Graphical and tabular reports generation for easy analysing of recorded
data
15.Cumulative, Trip-wise, Train-wise, Driver-wise and Date-wise report
generation
16.Master-Slave configuration
Applications
17.Speed indication for driver.
18.Administrative control of traction vehicle for traffic scheduling.
19.Vehicle trend analysis in case of derailment/accident.
20.Analysis of drivers operational performance to provide training, if
required.
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28. Technical Specifications
The system requires a wide operating voltage of 50 V DC to 140 V DC.
A. Operating conditions
Conditions Values
Temperature -5°C to +70°C
Relative humidity 95% (max)
Accuracy of Master & Slave ±1.0% of full scale deflection
B. Analogue indication
Factors Values
Scale spread over 240°
Illumination 12 equally spaced LEDs on dial circumference
Brightness control 0-100% in 10 steps
Dial size 120 mm
Dial colour White with black pointer & numerals
Max speed range 0-150, 0-160 & 0-180 Kmph (can be made as per
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customer’s request)

29. C. Digital indication
Features Values
LCD display 16x2 character alphanumeric LCD with backlit control
Time display HH:MM:SS on 24-hour scale
D. General
Factors Values
Size 145x215x160 mm (typical)
Weight: Master & Slave (approx) 3.5 kg (Master); 3.15 kg (Slave)
Odometer 7 digit with 1km resolution
Input speed sensing 2 inputs for opto-electronic pulse generator 200 or 100
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pulses/rev (configurable)
6. PIT WHEEL LATHE
Various type of wear may occur on wheal tread and flange due to wheel
skidding and emergency breaking. Four type of wear may occur as follows:-
21.Tread wear

30. 22.Root wear
23.Skid wear and
24.Flange wear
For maintaining the required profile pit wheel lathe are used. This lathe is
installed in the pit so that wheel turning is without disassembling the axle and
lifting the loco and hence the name “pit wheel lathe”
6.1 Wheel turning
Wheel turning on this lathe is done by rotating the wheels, both wheels of an
axle are placed on the four rollers, two for each wheel. Rollers rotate the
wheel and a fixed turning tool is used for turning the wheel.
Different gages are used in this section to check the tread profile. Name of
these gages are:-
25.Star gage
26.Root wear gage
27.Flange wear gage
28.J gage
j-gage is used to calculate the app. Dia of wheel.
Dia. Of wheel = 962 + 2 × (j-gage reading) ; mm
CAUSES OF WHEEL SKIDDING-
29.On excessive brake cylinder pressure (more than 2.5 kg/cm²).
30.Using dynamic braking at higher speeds.
31.When at the time of application of dynamic braking, the brakes of loco
would have already been applied. (in case of failure of D-1 Pilot valve).
32.Due to shunting of coaches with loco without connecting their
B.P./vacuum pipe.
33.Shunting at higher speeds.
34.Continue working when any of the brake cylinder of loco has gotten
jammed.
35.The time of application/release of brakes of any of the brake cylinder
being larger than the others.
36.When any of the axle gets locked during on the line.
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31. 7. FAILURE ANALYSIS
A part or assembly is said to have failed under one of the three conditions:-
When it becomes completely inoperable-occurs when the component breaks
into two or more pieces.When it is still inoperable but is no longer able to
perform its intended function satisfactorily- due to wearing and minor
damages.
When serious deterioration has made it unreliable or unsafe for continuous
use, thus necessitating its complete removal from service for repair or
replacement-due to presence of cracks such as thermal cracks, fatigue crack,
hydrogen flaking.
In this section we will study about:-
37.Metallurgical lab.
38.Ultrasonic test
39.Zyglo test and
40.RDP test.
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32. 7.1 Metallurgical lab.
Metallurgical lab. concern with the study of material composition and its
properties. Specimens are checked for its desired composition. In this section
various tests are conducted like hardness test, composition test e.g
determination of percentage of carbon, swelling test etc.
Function of some of the metal is tabulated in table below :-
S.No. Compound Function
1. Phosphorous Increase the fluidity property
2. Graphite Increase machinability
3. Cementide Increase hardness
4. Chromium Used for corrosion prevention
5. Nickel Used for heat resistance
6. Nitride rubber Oil resistance in touch of ‘O’ ring
7. Neoprene Air resistance & oil resistance in fast coupling
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in rubber block.
8. Silicon Heat resistance and wear resistance (upto 600
ºC ) use at top and bottom pore of liner.
7.2 Swelling test
Swelling test is performed for rubber in this test percentage increase in
weight of the rubber after immersing in solution is measured and increase in
weight should not be more than 20%. Two type of swelling test viz low swelling
and high swelling are performed in the lab. Three type of oil solution are used
for this purpose :- ASTM 1,ASTM 2 & ASTM 3
Procedure:
Select specimen for swelling test
1. Note the weight of the specimen
2. Put in the vessel containing ASTM 1 or ASTM 3
3. Put the oven at 100 ºC
4. Put the vessel in the oven for 72 hrs.
5. After 72 hrs. Weigh the specimen.

33. Rubber used in car :
Broadly there are two types of rubber:
1). Natural rubber- this has very limited applications. It is used in windows and
has a life of 1 year.
2). Synthetic rubber- this is further subdivided into five types.
41.VUNA-N (2 year life)
42.Polychloroprene or Neoprene (2 year life)
43.SBR (3 year life)
44.Betel (3 year life)
45.Silicone (3 year life).
VUNA-N rubber is used in oily or watery area, neoprene is used in areas
surrounded by oil and air while betel and silicone are used in areas subjected
to high temperatures such as in pistons.
When the fresh supply of rubber comes from the suppliers it is tested to know
its type.The test consists of two solutions, solution 1 and solution 2, which are
subjected to the vapors of the rubber under test and then the color change in
solution is used for determination of the type of rubber. The various color
changes are as follows:
46.Violet- natural rubber
47.Pink- nit rile
48.Green-SBR
When no color change is observed the vapours are passed through solution 2.
The colour change in solution 2 is: Pink- neoprene.
Silicone produces white powder on burning. If there is no result on burning
then the rubber is surely betel.
7.3 ULTRASONIC TESTING
In ultrasonic testing, very short ultrasonic pulse-waves with center
frequencies ranging from 0.1-15 MHz and occasionally up to 50 MHz are
launched into materials to detect internal flaws or to characterize materials.
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34. Ultrasonic testing is often performed on steel and other metals and alloys,
though it can also be used on concrete, wood and composites, albeit with less
resolution. It is a form of non-destructive testing.
7.4 ZYGLO TEST
The zyglo test is a nondestructive testing (NTD) method that helps to locate
and idetify surface defects in order to screen out potential failure-producing
defects. It is quick and accqurate process for locating surface flaws such as
shrinkage cracks, porosity, cold shuts, fatigue cracks, grinding cracks etc. The
ZYGLO test works effectively in a variety of porous and non-porous materials:
aluminum, magnesium, brass, copper, titanium, bronze, stainless steel,
sintered carbide, non-magnetic alloys, ceramics, plastic and glass. Various
steps of this test are given below:-
49.Step 1 – pre-clean parts.
50.Step 2 – apply penetrant
51.Step 3 – remove penetrant
52.Step 4 – dry parts
53.Step 5 – apply developer
54.Step 6 – inspection
7.5 RED DYE PENETRATION TEST (RDP)
Dye penetrant inspection (DPI), also called liquid penetrant inspection (LPI),
is a widely applied and low-cost inspection method used to locate surface-breaking
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defects in all non-porous materials (metals, plastics, or ceramics).
Penetrant may be applied to all non-ferrous materials, but for inspection of
ferrous components magnetic particle inspection is preferred for its subsurface
detection capability. LPI is used to detect casting and forging defects, cracks,
and leaks in new products, and fatigue cracks on in-service components.
Principles
DPI is based upon capillary action, where low surface tension fluid penetrates
into clean and dry surface-breaking discontinuities. Penetrant may be applied
to the test component by dipping, spraying, or brushing. After adequate
penetration time has been allowed, the excess penetrant is removed, a
developer is applied. The developer helps to draw penetrant out of the flaw
where a visible indication becomes visible to the inspector.

35. 8. SCHEDULE EXAMINATION
The railway traffic requires safety and reliability of service of all railway
vehicles. Suitable technical systems and working methods adapted to it, which
meet the requirements on safety and good order of traffic should be
maintained. For detection of defects, non-destructive testing methods - which
should be quick, reliable and cost-effective - are most often used. Inspection of
characteristic parts is carried out periodically in accordance with internal
standards or regulations; inspections may be both regular and extraordinary;
the latter should be carried out after collisions, derailment or grazing of railway
vehicles.
Maintenance of railway vehicles is scheduled in accordance with periodic
inspections and regular repairs. Inspections and repairs are prescribed
according to the criteria of operational life, limited by the time of operation of
a locomotive in traffic or according to the criteria of operational life including
the path traveled.
For the proper functioning of EMU shed and to reduce the number of
failures of diesel locos, there is a fixed plan for every loco, at the end of which
the loco is checked and repaired. This process is called scheduling
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36. 9. PERIODIC OVERHOULING
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40. This is a maintenance & inspection technique under which the whole
engines parts of any car whether they are a diesel car or emu car or memu car,
coaches , bogies etc after a certain period of time get be disassembled and the
defected parts or wear parts are fully replaced and the various tests been done
to identify the cracks or other disorder to ensure that no parts be fail during
there life after overhauling operation. And also well painted as per there
requirement .
REFERENCES:
 I.R.I.M.E.E, JAMALPUR
 R.D.S.O, LUCKNOW
 EMU SHED LIBRARY
 INTERNET
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