TUGHLAKABAD DIESEL LOCOMOTIVE SHED

Submitted by:Manish Kumar

Trainee

B.Tech. in Mechanical & Automotive Engineering

Delhi Technological University

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 Diesel Loco Shed, Tughlakabad. 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. Omkant Sharma, C.I.(D.T.C.), S.S.E of Diesel Loco Shed Tughlakabad and Mr. Devender Singh, Principal of Training School, D.M.E 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 various sections.

CONTENTS History Introduction of Diesel Shed TKD Fuel section Control room C.T.A cell Turbo Supercharger Expressor/Compressor Cylinder Head Bogie Fuel Injection Pump (FIP) CTA Cell Fuel Section Control Room Metallurgical Lab. Yearly (Mech.) Pit Wheel Lathe Running /Mech. /Goods Running /Mech./Mail Air Brake Speedometer

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

CLASSIFICATION1. 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 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.|~|

DIESEL SHED TUGHLAKABAD

INTRODUCTIONDiesel 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 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.

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 April1970. 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

Inception 22nd April 1970

Present Holding 147 Locomotives

19 WDM2 37 WDM3A 08 WDM3D 11 WDG3A 46 WDP 26 WDP3A

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

Accreditation ISO-9001-2000 & ISO 14001

SPECIAL MACHINES & PLANT

1. Pit wheel lathe machine

This machine is suitable for turn & re-profiles the wheels of locomotives.2. 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.

3. TECHNICAL INNOVATIONS 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.

4. 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 engines.

5. 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.

6. 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 loco pilots and other trainees.

Courses offered :- (regular)

Diesel Assistant to Diesel Loco Driver promotion course Diesel Assistant Refresher coarse Diesel Driver refresher course

Other courses:-

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

CONTROL ROOMIt 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 ‘overdue’ and control room can use the loco of another shed if that is available.

New and better operational loco have less LOC.

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 travelled ×100

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 engineers 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 Cell.

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 of trains.

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 locos.

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.

TURBO SUPERCHARGER

INTRODUCTION

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 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 burning it.

A turbocharger or turbo, is a gas compressor 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. 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. 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.

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.

AFTER COOLER

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.

TABLE 1

TYPE POWER COOLING1.ALCO 2600HP Water cooled2.ABB TPL61 3100HP Air cooled3.HISPANO SUIZA HS 5800 NG 3100HP Air cooled4. GE 7S1716 3100HP Water cooled5. NAPIER NA-295 2300,2600&3100HP Water cooled6. 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 supercharger, 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 clearance.

Surging- Back Pressure due to uneven gap in Nozzle Ring or Diffuser Ring.

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. Chimney gasket. Rubber ‘o’ Ring kit. Spring Washers. Lock Washer Rotor Stud.

FUEL OIL SYSTEM

INTRODUCTION

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-

FUELINJECTION 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 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 throughout 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 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.

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 fuel(cc)

15 mm 30 mm (full load)9 mm(Idling)

351 cc +5/-1034 cc +1/-5

17 mm 28 mm (full load)9 mm (Idling)

401 cc +4/-1145 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 TESTThe 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 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.SPRAY PRESSUREThe 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 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.NOZZLE CHATTEThe 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.

BOGIE

INTRODUCTION

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.

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 wheelsets, 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.

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:-

Bo-Bo 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.

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.

EXPRESSOR

INTRODUCTION

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 train.

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 exhausters whereas 6CD,3UC contain six cylinder and three exhausters.

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.

COMPRESSOR 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 outside 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.

AIR BRAKES

INTRODUCTION

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.

LAYOUT:-

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.

PEV

ARCR DV

DC

BC BC

DC

PEASD PEASD

FP

BP

GEBVPressuregauge

Cut offangle cock

Passenger alarmsystem

Guardemergencybrakesystem

Corebrakesystem

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.

VALVES

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.

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.

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.

SPEEDOMETER

INTRODUCTION

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.

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 feedback 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.

Salient features

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 7-digit odometer

User friendly Windows-based data extraction and analysis software Graphical and tabular reports generation for easy analysing of recorded data Cumulative, Trip-wise, Train-wise, Driver-wise and Date-wise report generation Master-Slave configuration

Applications

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.

Technical SpecificationsThe system requires a wide operating voltage of 50 V DC to 140 V DC.

A. Operating conditions

ConditionsValues

Temperature -5°C to +70°C

Relative humidity 95% (max)

Accuracy of Master & Slave ±1.0% of full scale deflectionB. Analogue indication

FactorsValues

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 customer’s request)

C. Digital indication

FeaturesValues

LCD display 16x2 character alphanumeric LCD with backlit control

Time display HH:MM:SS on 24-hour scaleD. General

FactorsValues

Size 145x215x160 mm (typical)

Weight: Master & Slave (approx) 3.5 kg (Master); 3.15 kg (Slave)

Odometer 7 digits with 1km resolution

Input speed sensing 2 inputs for opto-electronic pulse generator 200 or 100 pulses/rev (configurable)

CYLINDER HEAD

INTRODUCTION

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 inserts also.

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 250F 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 190F. 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 cylinder head.

Water holding capacity increased by increasing number of cores (14 instead of 11) Use of frost core plugs instead of threaded plugs, arrest tendency of leakage. 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.

Benefits:-

Better heat dissipation Failure reduced by reducing crack and eliminating sagging effect of fire deck area.

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 test.

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 penetration test.

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 head.

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 stroke. 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.

PIT WHEEL LATHE

INTRODUCTION

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:-

Tread wear Root wear Skid wear and 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”.

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:-

Star gage

Root wear gage Flange wear gage 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-

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 position. Due to shunting of coaches with loco without connecting their B.P./vacuum pipe. Shunting at higher speeds. Continue working when any of the brake cylinder of loco has gotten jammed. 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.

SCHEDULE EXAMINATION

INTRODUCTION

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 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:-

Major schedules

Minor schedule

MINOR SCHEDULES

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

TRIP-1

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.

TRIP-2

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.

MONTHLY-2 SEHEDULE

All the works done in T-2 schedule. All cylinder head valve loch check. Sump examination. Main bearing temperature checked. Expressor valve checked. Wick pad changed. Lube oil filter changed. Strainer cleaned. Expressor oil changed.

MAJOR SCHEDULES

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.

M-4 Schedule

(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.

YEARLY MECHANICAL

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 overhauled.

(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 leak.

(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 gauged.

(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 carried out.

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