Indian railways mechanical vocational training report 2 haxxo24 i~i
INDUSTRIAL TRAINING REPORT
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
Diesel Loco Shed, Tughlakabad. We are highly indebted to them for
their tremendous support and help during the completion of our training
We are grateful to Mr. V.K. MALIK, C.I. (D.T.C.) of Diesel Loco Shed
Tughlakabad and Mr. S.N. BASU 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 Diesel Training Centre and
Mr. V.K. MALIK
SEE Mechanical (DTC)
Introduction of Diesel Shed TKD
Fuel Injection Pump (FIP)
Pit Wheel Lathe
Running /Mech. /Goods
To study about Project Study
INDIAN RAILWAY HISTORY
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 kilometer 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. The Rajdhani Express and Shatabdi Express
are the fastest trains of India
1. Standard “Gauge” designations and dimensions:-
W = Broad gauge (1.67 m)
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
S = Shunting
4. “ Horse power ” designations from June 2002 (except WDP-1 & WDM-2
‘ 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.|~|
DIESEL SHED TUGHLAKABAD
Diesel locomotive shed is an industrial-technical setup, where repair and
maintenance works of diesel locomotives is carried out, so as to keep the loco
working properly. It contributes to increase the operational life of diesel
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
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.
The diesel shed usually has:-
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.
ABOUT DIESEL SHED TKD
Diesel Shed, Tughlakabad of Northern Railway is located in NEW DELHI. The
shed was established on 22nd
April 1970. 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-9001-200O& ISO 14001 OHSAS CERTIFICATION
is among of them. The Diesel 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, Diesel 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.
AT A GLANCE
Present Holding 147 Locomotives
Accreditation ISO-9001-2000 & ISO 14001
Covered area of shed 10858 SQ. MTR
Total Area of shed 1, 10,000 SQ. MTR
Staff strength sanction – 1357
On roll - 1201
Berthing capacity 17 locomotives
SPECIAL MACHINES & PLANT
Pit wheel lathe machine
This machine is suitable for turn & re-profiles the wheels of locomotives.
Effluent Treatment Plant:-
In order to provide pollution free environment, an ETP PLANT is installed.
Various effluents emitted from diesel shed are passed through the Plant. The
water thus collected is pollution free and is used for non drinking purposes
such as gardening and washing of the locomotives.
Based on day-to-day maintenance problems a large number of
innovations/modifications have been conceived and implemented in Diesel
Shed, TKD during 2003-2004 which have improved the reliability and downtime
of locomotives.Some of them are under.
Expressor performance test notch wise
Simulation of test stand facility on the loco itself with the help of
only two small fixtures.
Testing the performance of expressor in diesel locomotive
Cylinder head Stud Removal/ Tightening Arrangement
A simple device has been developed to help reduce the time and
effort taken in removal/tightening of cylinder head studs.
Diesel Training Centre-DTC
It was setup in the TKD shed premises in 1975 by the Northern Railway
with view to train diesel loco pilots. It also trains the Diesel Maintenance staff
to improve the availability of qualified manpower and improve the efficiency of
and quality of the technicians. It has five classrooms, a hall ,a Model room(with
sectional models of TSC, expressor, cylinder head LOP, governor etc.). A well
qualified team of instructors from the electrical and mechanical fields provides
a quality training to the p=loco pilots and other trainees.
Courses offered :- (regular)
Diesel Assistant to Diesel Loco Driver promotion course
Diesel Assistant Refresher coarse
Diesel Driver refresher course
Up gradation course of Diesel technicians
Electric traction to diesel traction conversion course
Course for Drivers, Shunters and Asstt. Drivers
3 years Apprentice technician(Diesel mechanical and electrical)
6 months Apprentice Technician(Diesel mechanical and electrical)
Vocational industrial training for B.Tech and Diploma student
The section is concern with receiving, storage and refilling of diesel and lube
oil. It has 3 large storage tanks and one underground tank for diesel
storage which have a combined storage capacity of 10,60, 000 liters.This
stock is enough to end for 15-16 days The fuel is supplied by truck from
IOC - Panipat refinery each truck diesel sample is treated in diesel lab
and after it in unloaded. Sample check is necessary to avoid water, kerosene
mixing diesel. Two fuel filling points are established near the control
room It also handles the Cardiam compound , lube oil. diesel is only for
loco use if the diesel samples are not according to the standard , the
delivery of the fuel is rejected. Viscosity of lube oil should be 100-1435 CST.
Water mixing reduces the viscosity.
Statement of diesel storage and received is made after every 10 days and the
report is send to the Division headquarter. The record of each truck, wagons
etc are included in it. The record of issued oil is also sending to headquarter.
After each 4 months. A survey is conducted by high level team about the
storage, records etc. 0.1% of total stored fuel oil is given for handling losses by
the HQ. The test reports of diesel includes the type of diesel ( high speed
diesel- Euro-3 with 0.035 % S), reason for test, inspection lot no, store tank no,
batch no. etc.
It controls and regulates the complete movement, schedules, duty of each
loco of the shed. Division level communications and contacts with each loco on
the line are also handled by the control room. Full record of loco fleet, failures,
duty, overdue and availability of locos are kept by the control room. It applies
the outage target of loco for the shed, as decided by the HQ. It decides the
locomotives mail and goods link that which loco will be deployed on which
train. It operates 116 Mail and 11Goods link from the shed locos. For 0-0
outage total 127 loco should be on line.
The schedule of duty, trains and link is decided by the control room according
to the type of trains. If the loco does not return on scheduled time in the shed
then the loco is termed as ‘ over due’ and control room can use the loco of
another shed if that is available.
The lube oil consumption is also calculated by the control room for each loco:-
Lube Oil Consumption (LOC) = Lube oil consumed in liters/ total kms
New and better operational loco have less LOC.
3.CTA (Chief Technical Assistance) CELL
This cell performs the following functions:-
Failure analysis of diesel 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
Preparation of full detailed failure reports of each loco and sub
systems, components after detailed analysis. The reports are then
sent to the Divisional HQ.
Correspondence with the headquarters is also done by the CTA
The failures analyzed are:-
Category 1 failures:- If the VIP trains loco fails or the train is delayed by the
failure of another trains loco failure. Failure of the single loco may delay a no
Non- reported failures:- the failure or delay of the local passenger trains for 2-3
hours is taken in this category. They are not reported to the higher levels and
can be adjusted in the section operations.
Foreign Railway-FR failures:- If the loco of one division fails in the other division
and affects the traffic seriously in that division. The correspondence in this
case is done by the cell.
Other failures are:-
1. Material failure:- may be due to poor quality, defective material and
defects in the manufacturing of the component. Component is replaced
if fails frequently.
2. Maintenance failures:- if lapse is by the maintenance workers. Inquiry is
done and punishment is set by CTA Cell on behalf of Sr. DME or
instructions are issued for better maintenance.
3. Crew lapse:- proper actions are take or instructions issued to the crew of
After every 4 years IOH of loco is done in the shed. After 8years POH of loco is
done at the Charbag loco shed –Lucknow. After 18 years rebuilding of loco is
done at DMW-Patiala. Total life of a loco is 36 years.
3. 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
An improvement in the naturally aspirated engines is the super-charged or
pressure charged engines. During the suction stroke, pressurised stroke of high
density is being charged into the cylinder through the open suction valve. Air
of higher density containing more oxygen will make it possible to inject more
fuel into the same size of cylinders and produce more power, by effectively
A turbocharger, or turbo, is a gas compresser 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
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.
Pressurising air increases its density, but due to compression heat develops. It
causes expansion and reduces the density. This effects supply of high-density
air to the engine. To take care of this, air is passed through a heat exchanger
known as after cooler. The after cooler is a radiator, where cooling water of
lower temperature is circulated through the tubes and around the tubes air
passes. The heat in the air is thus transferred to the cooling water and air
regains its lost density. From the after cooler air goes to a common inlet
manifold connected to each cylinder head. In the suction stroke as soon as the
inlet valve opens the booster air of higher pressure density rushes into the
cylinder completing the process of super charging.
The engine initially starts as naturally aspirated engine. With the increased
quantity of fuel injection increases the exhaust gas pressure on the turbine.
Thus the self-adjusting system maintains a proper air and fuel ratio under all
speed and load conditions of the engine on its own. The maximum rotational
speed of the turbine is 18000/22000 rpm for the Turbo supercharger and
creates max. Of 1.8 kg/cm2
air pressure in air manifold of diesel engine, known
as Booster Air Pressure (BAP). Low booster pressure causes black smoke due to
incomplete combustion of fuel. High exhaust gas temperature due to after
burning of fuel may result in considerable damage to the turbo supercharger
and other component in the engine.
MAIN COMPONENTS OF TURBO-SUPERCHARGER
Turbo- supercharger consists of following main components.
Gas inlet casing.
Blower casing with diffuser
Rotor assembly with turbine and rotor on the same shaft.
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.
This is a dynamically balanced component, as this has a very high rotational
LUBRICATING, COOLING AND AIR CUSHIONING
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.
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.
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.
Pressurised air from the blower casing is taken through a pipe inserted in the
turbo- supercharger to the space between the rotor disc and the intermediate
casing. It serves the purpose as described above.
It is a simple radiator, which cools the air to increase its density. Scales
formation on the tubes, both internally and externally, or choking of the tubes
can reduce heat transfer capacity. This can also reduce the flow of air through
it. This reduces the efficiency of the diesel engine. This is evident from black
exhaust smoke emissions and a fall in booster pressure.
Fitments of higher capacity Turbo Supercharger- following new
generation Turbo Superchargers have been identified by diesel shed TKD for
2600/3100HP diesel engine and tabulated in 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
TURBO RUN –DOWN TEST
Turbo run-down test is a very common type of test done to check the free
running time of turbo rotor. It indicates whether there is any abnormal sound
in the turbo, seizer/ partial seizer of bearing, physical damages to the turbine,
or any other abnormality inside it. The engine is started and warmed up to
normal working conditions and running at fourth notch speed. Engine is then
shut down through the over speed trip mechanism. When the rotation of the
crank shaft stops, the free running time of the turbine is watched through the
chimney and recorded by a stop watch. The time limit for free running is 90 to
180 seconds. Low or high turbo run down time are both considered to be
harmful for the engine.
ROTOR BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating
machine parts such as rotors of turbo subercharger,electric motors,fans,
turbines etc. The machine usually consists of two rigid pedestals, with
suspension and bearings on top.The unit under test is placed on the bearings
and is rotated with a belt. As the part is rotated, the vibration in the
suspension is detected with sensors and that information is used to determine
the amount of unbalance in the part. Along with phase information, the
machine can determine how much and where to add or remove weights to
balance the part.
ADVANTAGES OF SUPER CHARGED ENGINES
A super charged engine can produce 50 percent or more power than
a naturally aspirated engine. The power to weight ratio in such a case is
much more favorable.
Better scavenging in the cylinders. This ensures carbon free cylinders
and valves, and better health for the engine also.
Better ignition due to higher temperature developed by higher
compression in the cylinder.
It increases breathing capacity of engine
Better fuel efficiency due to complete combustion of fuel .
Defect in Turbochargers
Low Booster Air Pressure (BAP).
Oil throwing from Turbocharger because of seal damage or out of
Surging- Back Pressure due to uneven gap in Nozzle Ring or Diffuser
Must change components of Turbocharger.
Intermediate casing gasket.
Water outlet pipe flange gasket.
Water inlet pipe flange gasket.
Lube Oil inlet pipe rubber ‘o’ ring.
Turbine end Bearing.
Blower end Bearing.
Rubber ‘o’ Ring kit.
Lock Washer Rotor Stud.
4.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.
FUEL OIL SYSTEM
The fuel oil system consists of two integrated systems. These are-
FUEL INJECTION PUMP (F.I.P).
FUEL INJECTION SYSTEM.
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.
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
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.
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.
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.
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
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.
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 0
pressure 40 PSI:
Dia.of element(mm) Rack(mm) Required volume of
15 mm 30 mm(full load)
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.
.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.
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.
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
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
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.
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.
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
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.
At least two wheelset, composed of axle with a bearings and wheel at each
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
Brake equipment:-Brake shoes are used that are pressed against the tread
of the wheels.
Traction motors for transmission on each axle.
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
suspension. According to UIC classification two types of bogie in Indian Railway are:-
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.
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
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
to the track.
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.
In Indian Railways, the trains normally work on vacuum brakes and the
diesel locos on air brakes. As such provision has been made on every diesel
loco for both vacuum and compressed air for operation of the system as a
combination brake system for simultaneous application on locomotive and
In ALCO locos the exhauster and the compressor are combined into one unit
and it is known as EXPRESSOR. It creates 23" of vacuum in the train pipe and
140 PSI air pressure in the reservoir for operating the brake system and use in
the control system etc.
The expressor is located at the free end of the engine block and driven
through the extension shaft attached to the engine crank shaft. The two are
coupled together by fast coupling (Kopper's coupling). Naturally the expressor
crank shaft has eight speeds like the engine crank shaft. There are two types of
expressor are, 6CD,4UC & 6CD,3UC. In 6CD,4UC expressor there are six
cylinder and four exhauster whereas 6CD,3UC contain six cylinder and three
WORKING OF EXHAUSTER
Air from vacuum train pipe is drawn into the exhauster cylinders through the
open inlet valves in the cylinder heads during its suction stroke. Each of the
exhauster cylinders has one or two inlet valves and two discharge valves in the
cylinder head. A study of the inlet and discharge valves as given in a separate
diagram would indicate that individual components like (1) plate valve outer
(2) plate valve inner (3) spring outer (4) spring inner etc. are all
interchangeable parts. Only basic difference is that they are arranged in the
reverse manner in the valve assemblies which may also have different size and
shape. The retainer stud in both the assemblies must project upward to avoid
hitting the piston.
The pressure differential between the available pressure in the vacuum
train pipe and inside the exhauster cylinder opens the inlet valve and air is
drawn into the cylinder from train pipe during suction stroke. In the next
stroke of the piston the air is compressed and forced out through the discharge
valve while the inlet valve remains closed. The differential air pressure also
automatically open or close the discharge valves, the same way as the inlet
valves operate. This process of suction of air from the train pipe continues to
create required amount of vacuum and discharge the same air to atmosphere.
The VA-1 control valve helps in maintaining the vacuum to requisite level
despite continued working of the exhauster.
The compressor is a two stage compressor with one low pressure cylinder
and one high pressure cylinder. During the first stage of compression it is
done in the low pressure cylinder where suction is through a wire mesh
filter. After compression in the LP cylinder air is delivered into the discharge
manifold at a pressure of 30 / 35 PSI. Workings of the inlet and exhaust valves
are similar to that of exhauster which automatically open or close under
differential air pressure. For inter-cooling air is then passed through a radiator
known as inter-cooler. This is an air to air cooler where compressed air passes
through the element tubes and cool atmospheric air is blown on the out side
fins by a fan fitted on the expressor crank shaft. Cooling of air at this stage
increases the volumetric efficiency of air before it enters the high- pressure
cylinder. A safety valve known as inter cooler safety valve set at 60 PSI is
provided after the inter cooler as a protection against high pressure
developing in the after cooler due to defect of valves.
After the first stage of compression and after-cooling the air is again
compressed in a cylinder of smaller diameter to increase the pressure to 135-
140 PSI in the same way. This is the second stage of compression in the HP
cylinder. Air again needs cooling before it is finally sent to the air reservoir and
this is done while the air passes through a set of coiled tubes after cooler.
7. 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.
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.
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
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
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.
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.
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. The monitor is mounted on every driver’s place in a locomotive. It is
connected to the CPU by a serial link. Monitor transmits a driver, locomotive
and train identifications data to the CPU and receives data on travel speed,
partial distance traveled, real time and speedometer status from the CPU A
locomotive driver communicates with the speedometer using the monitor: a
keyboard and alphanumeric displays are used for authorization purposes,
travel speed values are monitored on analog and digital displays, whereas
alphanumeric displays, LEDs and a buzzer signal provide information on
speedometer and vehicle status.
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.
Light weight and compact in size
Adequate journey data recording capacity
Both analog and digital displays for speed
Both internal and external memories for data storage
Memory freeze facility
Stepless wheel wear compensation
Dual sensor opto electronic pulse generator for speed sensing
Over speed audio visual alarm
User friendly Windows-based data extraction and analysis software
Graphical and tabular reports generation for easy analysing of recorded
Cumulative, Trip-wise, Train-wise, Driver-wise and Date-wise report
Speed indication for driver.
Administrative control of traction vehicle for traffic scheduling.
Vehicle trend analysis in case of derailment/accident.
Analysis of drivers operational performance to provide training, if required.
The system requires a wide operating voltage of 50 V DC to 140 V DC.
A. Operating conditions
Temperature -5°C to +70°C
Relative humidity 95% (max)
Accuracy of Master & Slave ±1.0% of full scale deflection
B. Analogue indication
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
C. Digital indication
LCD display 16x2 character alphanumeric LCD with backlit control
Time display HH:MM:SS on 24-hour scale
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
9. CYLINDER HEAD
The cylinder head is held on to the cylinder liner by seven hold down studs
or bolts provided on the cylinder block. It is subjected to high shock stress and
combustion temperature at the lower face, which forms a part of combustion
chamber. It is a complicated casting where cooling passages are cored for
holding water for cooling the cylinder head. In addition to this provision is
made for providing passage of inlet air and exhaust gas. Further, space has
been provided for holding fuel injection nozzles, valve guides and valve seat
Components of cylinder head
In cylinder heads valve seat inserts with lock rings are used as replaceable
wearing part. The inserts are made of stellite or weltite. To provide
interference fit, inserts are frozen in ice and cylinder head is heated to bring
about a temperature differential of 250 F and the insert is pushed into recess
in cylinder head. The valve seat inserts are ground to an angle of 44.5
whereas the valve is ground to 45 to ensure line contact. (In the latest engines
the inlet valves are ground at 30° and seats are ground at 29.5°). Each cylinder
has 2 exhaust and 2 inlet valves of 2.85" in dia. The valves have stem of alloy
steel and valve head of austenitic stainless steel, butt-welded together into a
composite unit. The valve head material being austenitic steel has high level of
stretch resistance and is capable of hardening above Rockwell- 34 to resist
deformation due to continuous pounding action.
The valve guides are interference fit to the cylinder head with an interference
of 0.0008" to 0.0018". After attention to the cylinder heads the same is
hydraulically tested at 70 psi and 190 F. The fitment of cylinder heads is done
in ALCO engines with a torque value of 550 Ft.lbs. The cylinder head is a metal-
to-metal joint on to cylinder.
ALCO 251+ cylinder heads are the latest generation cylinder heads, used in
updated engines, with the following feature:
Fire deck thickness reduced for better heat transmission.
Middle deck modified by increasing number of ribs (supports) to increase its
mechanical strength. The flying buttress fashion of middle deck improves
the flow pattern of water eliminating water stagnation at the corners inside
Water holding capacity increased by increasing number of cores (14 instead
Use of frost core plugs instead of threaded plugs, arrest tendency of
Made lighter by 8 kgs (Al spacer is used to make good the gap between
rubber grommet and cylinder head.)
Retaining rings of valve seat inserts eliminated.
Better heat dissipation
Failure reduced by reducing crack and eliminating sagging effect of fire deck
Maintenance and Inspection
Cleaning: By dipping in a tank containing caustic solution or ORION-355
solution with water (1:5) supported by air agitation and heating.
Crack Inspection: Check face cracks and inserts cracks by dye penetration
Hydraulic Test: Conduct hyd. test (at 70 psi, 200°F for 30 min.) for checking
water leakage at nozzle sleeve, ferrule, core plugs and combustion face.
Dimensional check :
Face seat thickness: within 0.005" to 0.020"
Straightness of valve stem: Run out should not exceed 0.0005"
Free & Compressed height (at 118 lbs.) of springs: 3 13/16" & 4 13/16"
Checks during overhauling:
Ground the valve seat insert to 44.5°/29.5°, maintain run out of insert within
0.002" with respect to valve guide while grinding.
Grind the valves to 45°/30° and ensure continuous hair line contact with valve
guide by checking colour match.
Ensure no crack has developed to inserts after grinding, checked by dye
Make pairing of springs and check proper draw on valve locks and proper
condition of groove and locks while assembling of valves.
Lap the face joint to ensure leak proof joint with liner.
Blow by test:
On bench blow by test is conducted to ensure the sealing effect of cylinder
Blow by test is also conducted to check the sealing efficiency of the
combustion chamber on a running engine, as per the following procedure:
Run the engine to attain normal operating temperature (65°C)
Stop running after attaining normal operating temperature.
Bring the piston of the corresponding cylinder at TDC in compression
Fit blow-by gadget (Consists of compressed air line with the provision of a
pressure gauge and stopcock) removing decompression plug.
Charge the combustion chamber with compressed air.
Cut off air supply at 70 psi. Through stop cock and record the time when it
comes down to zero.7 to 10 secs is OK.
10. PIT WHEEL
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:-
Skid wear and
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”
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 tocheck the tread profile. Name of
these gages are:-
Root wear gage
Flange wear 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-
On excessive brake cylinder pressure (more than 2.5 kg/cm²).
Using dynamic braking at higher speeds.
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).
Continue working , when C-3-W Distributor valve P/G handle is in wrong
Due to shunting of coaches with loco without connecting their B.P./vacuum
Shunting at higher speeds.
Continue working when any of the brake cylinder of loco has gotten
The time of application/release of brakes of any of the brake cylinder being
larger than the others.
When any of the axle gets locked during on the line.
11. 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
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,
In this section we will study about:-
Zyglo test and
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
in rubber block.
8. Silicon Heat resistance and wear resistance (upto 600
ºC ) use at top and bottom pore of liner.
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 listed below:-
1. 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.
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.
VUNA-N (2 year life)
Polychloroprene or Neoprene (2 year life)
SBR (3 year life)
Betel (3 year life)
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:
Violet- natural rubber
Pink- nit rile
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.
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.
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.
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:-
Step 1 – pre-clean parts.
Step 2 – apply penetrant
Step 3 – remove penetrant
Step 4 – dry parts
Step 5 – apply developer
Step 6 – inspection
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 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.
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.
12. 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
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 diesel 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. There are
two types of schedules which are as follows:-
Schedule is done by the technicians when the loco enters the shed.
After 15 days there is a minor schedule. The following steps are done every
minor schedule & known as SUPER CHECKING.
The lube oil level & pressure in the sump is checked.
The coolant water level & pressure in the reservoir is checked.
The joints of pipes & fittings are checked for leakage.
The check super charger, compressor &its working.
The engine is checked thoroughly for the abnormal sounds if there is any.
F.I.P. is checked properly by adjusting different rack movements.
This process should be done nearly four hour only. After this the engine
is sent in the mail/goods running repairs for repairs. There are following types
of minor schedules:-
T-1 SHEDULE AFTER 15 DAYS
T-2 SHEDULE AFTER 30 DAYS
T-1 SHEDULE AFTER 45 DAYS
M-2 SHEDULE AFTER 60 DAYS
T-1 SHEDULE AFTER 75 DAYS
T-2 SHEDULE AFTER 90 DAYS
T-1 SHEDULE AFTER 105 DAYS
Fuel oil & lube check.
Expressor discharge valve.
Flexible coupling’s bubbles.
Turbo run down test.
Record condition of wheels by star gauge.
Record oil level in the axle caps for suspension bearing.
All the valves of the expressor are checked.
Primary and secondary fuel oil filters are checked.
Turbo super charger is checked.
Under frame are checked.
Lube oil of under frame checked.
All the works done in T-2 schedule.
All cylinder head valve loch check.
Main bearing temperature checked.
Expressor valve checked.
Wick pad changed.
Lube oil filter changed.
Expressor oil changed.
These schedules include M-4, M-8 M-12 and M-24. The M-4 schedule is
carried out for 4 months and repeated after 20 months. The M-8 schedule is
carried out for 8 months and repeated after 16 months. The M-12 is an annual
schedule whereas the M-24 is two years.
Besides all of these schedules for the works that are not handled by the
schedules there is an out of course section, which performs woks that are
found in inspection and are necessary. As any Locomotive arrives in the
running section first of all the driver diary is checked which contains
information about the locomotive parameters and problem faced during
operation. The parameters are Booster air pressure (BAP), Fuel oil pressure
(FOP), Lubricating oil pressure (LOP) and Lubricating oil consumption (LOC).
After getting an idea of the initial problems from the driver’s diary the T-1
schedule is made for inspection and minor repairs.
(1). Run engine; check operation of air system safety valves and expressor
crankcase lube oil pressure.
(2). Stop engine; carry out dry run operational test, check FIP timing and
uniformity of rack setting and correct if necessary.
(3). Engine cylinder head:-Tighten all air and exhaust elbow bolts, check valve
clearance, exhaust manifold elbow etc.
(4). Engine crankcase cover:-Remove crankcase cover and check for any
foreign material. Renew gaskets.
(5). Clean Strainer and filters, replace paper elements.
(6). Compressed air and vacuum system:-Check, clean and recondition rings,
piston, Intake strainers, and inlet and exhaust valve, lube oil relief valve,
unloading valve. Drain, clean and refill crankcase.
(7). Radiator fan- tightens bolts and top up oil if necessary.
(8). Roller bearing axle boxes.Check for loose bolts, loss of grease, sign of
overheating. Remove covers, clean and examine roller races and cages for
defects. Carry out ultrasonic test of axles.
(9). Clean cyclonic filters, bag filters and check the condition of rubber bellows
of air intake system.
(10). Renew airflow indicator valve.
(11). Carry out blow bye test and gauge wheel wears.
In this section, major schedules such as M-24, M48 and M-72 are carried out.
Here, complete overhauling of the locomotives is done and all the parts are
sent to the respective section and new parts are installed after which load test
is done to check proper working of the parts. The work done in these sections
are as follows:
1). Repeating of all items of trip, quarterly and monthly schedule.
2). Testing of all valves of vacuum/compressed air system. Repair if necessary.
3). Replacement of coalesce element of air dryer.
(4). Reconditioning, calibration and checking of timing of FIP is done. Injector is
(5). Cleaning of Bull gear and overhauling of gear-case is done.
(6). RDP testing of radiator fan, greasing of bearing, checking of shaft and
keyway. Examination of coupling and backlash checking of gear unit is done.
(7). Checking of push rod and rocker arm assembly. Replacement is done if
bent or broken. Checking of clearance of inlet and exhaust valve.
(8). Examination of piston for cracks, renew bearing shell of connecting rod
fitment. Checking of connecting rod elongation.
(9). Checking of crankshaft thrust and deflection. Shims are added if deflection
is more then the tolerance limit.
(10). Main bearing is discarded if it has embedded dust, gives evidence of
fatigue failure or is weared.
(11). Checking of cracks in water header and elbow. Install new gaskets in the
air intake manifold. Overhauling of exhaust manifold is done.
(12). Checking of cracks in crankcase, lube oil header, jumper and tube leakage
in lube oil cooler. Replace or dummy of tubes is done.
(13). Lube oil system- Overhauling of pressure regulating valves, by pass valve,
lube oil filters and strainers is done.
(14). Fuel oil system- Overhauling of pressure regulating valve, pressure relief
valve, primary and secondary filters.
(15). Checking of rack setting, governor to rack linkage, fuel oil high-pressure
line is done.
(16). Cooling water system- draining of the cooling water from system and
cleaning with new water carrying 4 kg tri-phosphate is done. All water system
gaskets are replaced. Water drain cock is sealed. Copper vent pipes are
changed and water hoses are renewed.
(17). Complete overhauling of water pump is done. Checking of impeller shaft
for wear and lubrication of ball bearing. Water and oil seal renewal.
(18). Complete overhauling of expressor/compressor, pistons rings and oil seal
renewed. Expressor orifice test is carried out.
(19). Complete overhauling of Turbo supercharger is done. Dynamic balancing
and Zyglo test of the turbine/impeller is done. Also, hydraulic test of complete
Turbo supercharger is done.
(20). Overhauling of after-cooler is done. Telltale hole is checked for water
(21). Inspection of the crankcase cover gasket and diaphragm is done. It is
renewed if necessary.
(22). Rear T/Motor blower bearing are checked and changed. Greasing of
bearing is done.
(23). Cyclonic filter rubber bellows and rubber hoses are changed. Air intake
filter and vacuum oil bath filter are cleaned and oiled.
(24). Radiators are reconditioned, fins are straightened hydraulic test to detect
leakage and cleaning by approved chemical.
(25). Bogie- Checking of frame links, spring, equalizing beam locating roller pins
for free movement, buffer height, equalizer beam for cracks, rail guard
distance is done. Refilling of center plate and loading pads is done. Journal
bearings are reconditioned.
(26). Axle box- cleaning of axle box housing is done.
(27). Wheels- inspection for fracture or flat spot. Wheel are turned and
(28). Checking of wear on horn cheek liners and T/M snubber wear plates.
(29). Checking of brake parts for wear, lubrication of slack adjusters is done.
Inspection for fatigue, crack and distortion of center buffers couplers, side
buffers are done.
(30). Traction motor suspension bearing- cleaning of wick assembly, checking
of wear in motor nose suspension. Correct fitment of felt wick lubricators is
ensured. Axle boxes are refilled with fresh oil. Testing of all pressure vessels is
Examination while Engine is running.
(32). Expressor orifice test is performed. Engine over sped trip assembly
operation, LWS operation are checked. Checking of following items is done:
Water and oil leakage at telltale hole of water pump, turbo return pipes for
leakage and crack, air system for leakage, fuel pump and pipes for leakage,
exhaust manifold for leaks, engine lube oil pressure at idle, turbo for smooth
run down as engine is stopped. Difference in vacuum between vacuum
reservoir pipe and expressor crankcase & and pressure difference across lube
oil filters at idle and full engine speed are recorded.
(33). Brakes at all application positions are checked. Checking of fast and
flexible coupling is done and the expressor is properly aligned. Inspection of
camshaft. Lubrication of hand brake lever and chain.
(37). Speedometer- Overhaul, testing of speed recorder and indicator, pulse
generator is done.
(38). Additional items for WDP1:-Overhauling and operation of TBU is done,
center pivot pin is checked, and CPP bush housing liners are checked for wear,
inspection of vibration dampers for oil leakage and their operation. RDP test is
done to check for cracks at critical location in the bogie frame. Checking of coil
springs for free height.
(39). Additional items for WDP2 locos:-Checking for cracks bogie frame
and bolster. Checking of hydraulic dampers for oil leakage. Check coil
spring for free height. Zyglo test of guide link bolts is performed.
Examination of taper roller bearing for their condition and clearance is
done. Check and change center pivot liners. Checking of tightness of
nuts on brake head pin. Disassembly, cleaning, greasing, repairing,
replacement of brake cylinder parts is done. Ultrasonic test of axles is
performed. Visual Examination of suspension springs for crack and
breakage. Checking of free and working height of spring. Inspection of
bull gear for any visible damage is done and the teeth profile is checked.
Test loco on load box as per RDSO standards.
Project title :- To study about turbo supercharger of
A turbosupercharger, or turbo, is a gas compressor that is used for forced-
induction of an internal combustion engine. It increases the density of air
entering the engine to create more power.
A turbosupercharger has the compressor powered by a turbine, driven by the
engine's own exhaust gases. The turbine and compressor are mounted on a
shared shaft. The turbine converts exhaust heat and pressure to rotational
force, which is in turn used to drive the compressor. The compressor draws in
ambient air and pumps it in to the intake manifold at increased pressure,
resulting in a greater mass of air entering the cylinders on each intake stroke.
Turbosupercharging dramatically improves the engine's specific power, power-
to-weight ratio and performance characteristics which are normally poor in
non-turbosupercharged diesel engines.
TURBOS USED IN DIESEL LOCOMOTIVE
In diesel locomotives, different turbos are used for different engines on the
basis of their horsepower and make. Still, their general function remains the
same i.e. to provide compressed air to the engine by employing the energy of
exhaust gases. The exhaust manifold is connected to the inlet of the
turbocharger. The exhaust gases enter the gas inlet casing where they are
directed towards the nozzle ring. The function of the nozzle ring is to guide the
exhaust gases and reduce shock on the turbine blades. The exhaust gases
impinge on the turbine blades and cause the turbine to rotate on their way out
to the atmosphere through the chimney.
The rotating turbine causes the impeller of the compressor to rotate along
with it since they are mounted on the same shaft. The compressor starts
sucking air through the air inlet casing and compresses it due to the centrifugal
action of the impeller. After leaving the impeller, the air gets compressed
further in the diffuser vanes. From here the compressed air is passed into the
blower casing, which guides the air to an aftercooler. The function of the
aftercooler is to cool the compressed air and consequently reduce its specific
volume. The pressure of this compressed air is in the range of 1.2-1.8 kg/cm2,
and this is known as BOOSTER AIR PRESSURE (BAP). This compressed air is then
introduced into the air gallery, which is connected to the intake valves of all
Turbosuperchargers from the following manufacturers are used in
GENERAL ELECTRIC (GE)
COMPARISON OF DIFFERENT TURBO MAKES
The specifications of the turbos used in diesel locomotives are as
Power Rating: 2600 HP
Cooling System: Water Cooled
Rundown Time: 80-190 seconds
Power Rating: 2300 HP
Cooling System: Water Cooled
Rundown Time: 60-120 seconds
Power Rating: 2600 HP
Cooling System: Water Cooled
Rundown Time: 60-120 seconds
Power Rating: 3100 HP
Cooling System: Water Cooled
Rundown Time: 60-120 seconds
5. ABB-TPR 61
Power Rating: 3300 HP
Cooling System: Air Cooled
Rundown Time: 60-120 seconds
Power Rating: 2300 HP
Cooling System: Water Cooled
Rundown Time: 20-60 seconds
Power Rating: 2600 HP
Cooling System: Water Cooled
Rundown Time: 20-60 seconds
Power Rating: 3100 HP
Cooling System: Water Cooled
Rundown Time: 20-60 seconds
9. GE-3100 SINGLE DISCHARGE
Power Rating: 3100 HP
Cooling System: Water Cooled
10. GE-3100 DOUBLE DISCHARGE
Power Rating: 3100 HP
Cooling System: Water Cooled
*Has two outlets for air in the blower casing and hence uses
11. HISPANO SUIZA-3100
Power Rating: 3100 HP
Cooling System: Air Cooled
Power Rating: 4000 HP
ALCO FRONT VIEW
GE (DOUBLE DISCHARGE) FRONT VIEW
GE (DOUBLE DISCHARGE) TOP VIEW
GE (DOUBLE DISCHARGE) BOTTOM VIEW
GE (DOUBLE DISCHARGE) ASSEMBLY
TURBO OPERATING DIFFICULTIES:
Operating difficulties can be prevented providing the daily turbocharger
operating data is measured and regular maintenance and inspection routines
are adhered to.
To assist in identifying causes of performance deterioration, the following table
has been formed:
PROBABLE CAUSE REMEDIAL MEASURES
Engine starts running but the
turbocharger does not.
Foreign matter/debris caught
between the turbine blade tips
and the shroud ring.
Blade tips rubbing the shroud
Provide cleaning and eliminate
the cause for the ingress of the
Inspect and replace with new
surging during operating.
Fouling of turbine nozzle,
Engine Cylinder unbalance.
Note: Rapid Changes of the
engine load, particularly during
shut-down can cause
Cleaning of the turbine side of
turbocharger as required.
Refer to Engine Builders
Exhaust gas temperature higher
Fouling or damage to turbine
nozzle or turbine blades.
Lack of air e.g.: dirty air filter.
Exhaust back pressure too high.
Charge air cooler dirty, cooling
water temperature too high.
Engine fault in fuel injection
Cleaning the turbine side of the
turbocharger or component
Clean as required.
Clean and adjust as Makers
Charge air (boost) pressure
lower than normal.
Pressure gauge faulty or
connection to it is leaking.
Gas leakage at engine exhaust
Dirty Air filter, causing pressure
Turbine blades or nozzle ring
See Engine Builders Instruction
Clean air as required.
Cleaning of complete
Inspect and replace as
Charge air pressure (boost)
higher than normal.
Pressure gauge reading
Nozzle ring clogged with carbon
Clean as required.
The overhauling and servicing of a turbosupercharger is broadly
divided into five parts which are:
Dismantling of the turbo
Cleaning of the turbo
Inspection of different parts
Repair and rotor balancing
Assembly of the turbo
Engine Overload, engine output
higher than expected.
Fault in engine fuel injection
Consult Engine Builders
Consult Engine Builders
Turbocharger Vibration Severe unbalance of rotor due
to dirt or damaged turbine
Bent rotor shaft.
Rebalance the rotor assembly.
Inspect and replace as
Inspect and replace as
DISMANTLING OF THE TURBO
Dismantling of a turbo requires trained personnel and special tools (allen keys,
spanners, suspension yoke, support, etc). It is a complicated process and
should be done very carefully after referring to the manufacturer’s instruction
CLEANING OF THE TURBO
Cleaning work includes regular visual checks and the cleaning of parts to
ensure the correct functioning of the turbo.
The following figure explains the various symbols used in the previous
Deposits often form on the nozzle ring and the turbine blades. Impaired
efficiency and performance of the engine are the result.
Thick and irregular deposits can also result in an un-permissible unbalance of
Cleaning of the cooling water passage of gas outlet casing:
Commercial HCL of 5% concentration is used for cleaning and defurring. An
inhibitor is added to reduce the corrosion of cast iron.
Neutralisation with 5% NaOH (alkaline) solution follows the acid wash.
Fresh water is used foe flushing/rinsing.
All casing gaskets are replaced.
Gas inlet casing:
Deposits are cleaned with soft wire brush and with either diesel/kerosene +
20% mineral oil solution (80/20 solution).
Cleaning of the sealing air ducts:
The carbon deposits are dissolved and cleaning is done with the help of flexible
wire for ensuring free passage.
Compressed air is used to check that the sealing air ducts in the bearing casing
are unobstructed / unchoked.
It is cleaned with 80% kerosene/diesel + 20% mineral oil solution (i.e. 80/20
AIR OUTLET CASING:
The deposits are cleaned with soft wire brush and 80/20 solution.
The turbine blades can be cleaned by glass bead blasting. The seating areas for
compressor wheel set, thrust bearing and floating bushes (Bearing compressor
side + Turbine side) are protected by means of rubber sleeve. The cleaning of
the compressor wheel set is carried out with 80/20 solution and therefore with
malmal (piece of cloth).
Rotating parts are thoroughly cleaned uniformly as uneven residual deposits
lead to unbalance.
All bearing parts, bearing covers are cleaned in 80/20 solution and with malmal
(piece of cloth). Special care is taken to clean the carbon deposits from the “O”
ring grooves and the oil supply/oil drain lines.
INSPECTION OF THE TURBO:
After dismantling and cleaning of the turbo, it is inspected for any faults. All
the clearances and blade conditions are checked and a note of all the repair
work needed is made.
REPAIR AND BALANCING OF ROTOR:
Various parts of the turbo are repaired as necessary. The rotor is examined
carefully and any distorted turbine blade is ground with a grinder so that it is
smooth again. The rotor is then checked if it is unbalanced and is balanced on a
Rotor Balancing Machine if needed.
In the course of manufacture, following parts are balanced individually:
Sets of compressor wheel
While the engine is running, many reasons may cause unbalance to the rotor:
Mechanical damages on the rotor, i.e. foreign bodies.
Uneven deposits of layer of dirt/carbon.
Abrasion on the compressor or the turbine caused by hard particles in the
intake air or in the exhaust gas.
Balancing must be done when:
Rotating components feature mechanical damages.
After reblading of turbine.
After repairs on the inducer or compressor wheel.
After replacing the inducer or compressor wheel.
Balancing is not required when:
A new bladed shaft is assembled into the turbocharger.
If, due to a change of specification, the set of wheels has to be changed for a
ABRO ROTOR BALNCING MACHINE
GE ROTOR ON BALANCING MACHINE
TURBO RUNDOWN TIME
The Turbo Rundown Time (TRD) of a turbo is the total time taken by the turbo
to come to a standstill, measured from the instant the crankshaft of the engine
stops. This time should be within a certain limit prescribed by the
manufacturer. If not so, it indicates a fault in the turbo. The rundown times of
different turbos have been mentioned earlier.
Turbo Rundown Test (for WDM-2 Loco)
This test is to be conducted if the Booster (Turbocharger in WDM-2 pidgin) is
not developing proper pressure during a run.
1. Secure the loco: Keep the A9 (Train Brake lever) in released condition;
keep the SA9 (Loco brake lever) in an applied condition; switch off the
GF (Generator Field); keep the reverser in neutral condition; and put the
ECS (Engine control switch) in the run mode.
2. Ensure that the water temperature is higher than 49 degrees Celsius.
3. The driver should climb on top of the hood and sight the turbine of the
turbocharger through the chimney.
4. The assistant should raise the engine to 4th notch rpm and allow the
engine to stabilize in speed.
5. The assistant should now shut the engine down by operating the MUSD
(Multiple Unit Shut Down) breaker on the control stand.
6. As the engine begins to stop turning, the assistant must quickly get
down and come to the hood door to the Expressor.
7. He must give a signal to the driver as to the instant the huge engine
stops rotating by looking at the crankshaft of the engine coupled to the
8. The driver must count the number of seconds the exhaust turbine takes
to come to a stop, from the instant the engine has come to a standstill.
9. If the turbine (which revolves at 18,000 to 19,000 rpm) takes more than
90 seconds then it is a good turbocharger, any reduction in the period of
spinning down is an indication of a faulty turbo.|~|
TKD SHED LIBRARY