diesel shed izzatnagar report part 2

INDIAN RAILWAY HISTORY

INTRODUCTION

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 kilometer(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. Totel number

of shed in India is 50.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 kilo meter is electrified &

almost all electrified sections use 25,000 V AC. Indian railways uses four rail

track gauges|~|

report on DIESLE LOCO SHED IZZATNAGAR NE RAILWAY

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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

CLASSIFICATION

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

G= Goods

S = Shunting

4. “ Horse power ” designations from June 2002 (except WDP-1 & WDM-2

LOCOS)

‘ 3 ’ For 3000 horsepower



‘ A ’ For extra 100 horsepower

‘B’ For extra 200 horsepower and so on.


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Hence ‘WDM-3A’ indicates a broad gauge loco with diesel-electric traction. It

is for mixed services and has 3100 horsepower.

DIESEL LOCO SHED IZZATNAGAR

Fig (1)

INTRODUCTION

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.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 section


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Machine shop and welding facilities

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.

TECHNICAL INNOVATIONS

Based on day-to-day maintenance problems a large number of

innovations/modifications have been conceived and implemented in Diesel

Shed, IZN 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 engines.

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.

CONTROL ROOM

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


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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.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 liter/ total kms trevelled × 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.


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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

Fig (2)


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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 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


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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.

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


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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.

ADVANTAGES OF SUPER CHARGED ENGINES


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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 .

FUEL OIL SYSTEM

Fig (3)

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


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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.


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Fig (4)

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. 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.

BOGIE


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Fig (5)

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 wheel set, composed of axle with a bearings and wheel at each

end. Axle box suspension to absorb shocks between the axle bearings and the

bogie frame. The axle box suspension usually consists of a spring between the bogie frame and axle bearings to permit up and down movement, and


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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

Fig (6)

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.

EXHAUSTER


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Fig (7)

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

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


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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 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.


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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 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


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TELPRO is used in the most of the locomotive. Features and other technical specification of this speedometer are given below.

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.

CYLINDER HEAD

Fig (8)

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


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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.


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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"

PIT WHEEL LATHE

Fig (9)

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


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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


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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


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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


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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.


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(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

Fig (10)

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.


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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.


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(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.


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(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


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bull gear for any visible damage is done and the teeth profile is checked. Test loco on load box as per RDSO standards.

diesel shed izzatnagar report part 2

Presentations & Public Speaking

broad gauge loco

fleet of indian railway

meter gauge

medium gauge

ministry of railways

shed working

standard gauge designations

narrow gauge 762mm4