Docstoc

training report railway

Document Sample
training report railway Powered By Docstoc
					           VOCATIONAL SUMMER TRANING




SUBMITTED TO:                       SUBMITTED BY:

Mr. RAJBALI                         SADIK HUSAN
WM & Principal of                    Roll No: 08ME43

BTC , Railway Workshop      B.Tech.(ME) IIIrd Yr.

Izatnagar, Bareilly                 F.E.T. MJPRU,BAREILLY
    N.E. RAILWAY BAREILLY
WORKSHOP IZATNAGAR, BARILLY
INDIAN RAILWAY
 This project would have been just a dream without a guidance and
support of our CWM Mr.M P SINH & AW M/C WM
Mr.RAJBALI


       Their role has been instrumental in the knowledge and
experience that I have gained in the past 4 weeks at
MECHANICAL WORKSHOP of NORTH EASTERN
RAILWAY, IZATNAGAR BAREILLY. I owes my heartiest
thanks to him.

       I would also like to thanks Mr.DC DUBEY (S.E), for giving
me helpful tips at every stage. I feel blessed to be working with
their team. I am grateful to the management of our college for
providing all kinds of possible support, ensuring that Ichieve
success in my work.
       Further I would like to deliver my special thanks to Mr.
Ranjan Dutta (JE), Mr. Parvej Alam (INSP) and all other whose
guides us with us full information. I have tried our best to learn and
written briefly in my project.




                Indian Railways
               Departmental Undertaking of The

               Ministry of Railways, Government of
Type
               India

               Rail transport
Industry

               16 April 1857[1]
Founded

               New Delhi, Delhi, India\
Headquarters

               India
Area served

               Rail transport, Cargo transport, Services,
Products
               more...

               88,355 crore (US$19.7 billion) (2009-10)[2]
Revenue
             9,595 crore (US$2.14 billion) (2009-10)[2]
Net income

             Republic of India (100%)
Owner(s)

             17 Railway Zones
Divisions




                   CONTENTS:



         INTRODUCTION OF B.G. COACHES.

         AIR BRAKE SYSTEM & BOGIE WITH
          BRAKE     GEAR

         MACHINES USED IN MACHINE SHOP &
          WHEEL SHOP

         CARRIAGE WORKS                 IN    IZATNAGAR
          WORKSHOP
INTRODUCTION OF B.G. COACH
In India mainly three types of Railway coaches are running which are on the
base of there guage.

    Broad Guage
    Meter Guage
    Narrow Guage

         In Izatnagar workshop Overhauling of M.G. & B.G. Coaches and
locomotives are performed

            In India slip coach refers to a coach that is designated to
terminate its journey at a station prior to the final destination of the rest of
the train. The more accurate term is sectional carriage. The coach or coaches
are left behind after being detached from the rest of the train. In India this is
done only after the train comes to a halt; the vacuum and brake connections
have to be tested before the rest of the train can leave.

            The term 'slip coach' is from an earlier era, however. A long time
back it was the practice in the UK to uncouple some cars or coaches on the
run, without stopping (this was called 'slipping' the coaches), at some
stations. In such an operation, the slip coach had its own special guard who
controlled the detachment, and then braked the coach as it travelled under its
own momentum towards the platform at the station. This avoided delays for
the main part of the train which did not have to stop at the station. This
practice continued for quite some time in the UK (until the 1960s), and slip
coach usually refers to this practice in British terminology. But in India the
term has come to mean coaches that are detached even though they are not
slipped on the run.

          E.g., 5014 Ranikhet Exp. from Kathgodam has 2 SL coaches and
one AC-2T coach that are slip coaches for Dehradun. These are detached
and attached to the 4265 Mail. Another slip coach (SL) for Jammu Tawi is
detached and attached to the 3151 Express.
          A through coach is like a slip coach, except that it is later re-attached to
another train after being detached from the first one. Thus, the passengers in the coach do
not have to change trains for their destination, even if no through train exists for that
route.

      63,140 total kilometers covered.
      8,702 passenger trains.
      6,856 railway stations.
      14 million passengers a day


General layout of a B.G. Coach
AIR BRAKE
SYSTEM
The ability of the railway vehicle to safely stop from the maximum speed
within the specified braking distance under any conditions is one of the most
important safety features. There is a rule saying that "any vehicle may start
moving but every vehicle must stop".

Prior to the introduction of air brakes, stopping a train was a difficult
business. In the early days when trains consisted of one or two cars and
speeds were low, the engine driver could stop the train by reversing the
steam flow to the cylinders, causing the locomotive to act as a brake.
However, as trains got longer, heavier and faster, and started to operate in
mountainous regions, it became necessary to fit each car with brakes, as the
locomotive was no longer capable of bringing the train to a halt in a
reasonable distance.

The introduction of brakes to railcars necessitated the employment of
additional crew members called brakemen, whose job it was to move from
car to car and apply or release the brakes when signaled to do so by the
engineer with a series of whistle blasts. Occasionally, whistle signals were
not heard, incorrectly given or incorrectly interpreted, and derailments or
collisions would occur because trains were not stopped in time.

Brakes were manually applied and released by turning a large brake wheel
located at one end of each car. The brake wheel pulled on the car's brake
rigging and clamped the brake shoes against the wheels. As considerable
force was required to overcome the friction in the brake rigging, the
brakeman used a stout piece of wood called a "club" to assist him in turning
the brake wheel.

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. The mechanical linkage can become quite
elaborate, as it evenly distributes force from one pressurized air cylinder to 8
or 12 wheels.

The pressurized air comes from an air compressor in the locomotive and is
sent from car to car by a train line made up of pipes beneath each car and
hoses between cars. The principal problem with the straight air braking
system is that any separation between hoses and pipes causes loss of air
pressure and hence the loss of the force applying the brakes. This deficiency
could easily cause a runaway train. Straight air brakes are still used on
locomotives, although as a dual circuit system, usually with each bogie
(truck) having its own circuit.

Two types of air brake system are :

1.Single Pipe System:
2:Twine pipe system


                               pipe System




Brake system types most frequently used for railway vehicles:

      Pneumatic (air pressure) brake,
      Electromagnetic rail brake,
      Hydraulic brake,
      Dynamic brake.
Introduction
                The air brake is the standard, fail-safe, train brake used by
railways all over the world. In spite of what you might think, there is no
mystery to it. It is based on the simple physical properties of compressed
air. So here is a simplified description of the air brake system.
Basics

            A moving train contains energy, known as kinetic energy, which
needs to be removed from the train in order to cause it to stop. The simplest
way of doing this is to convert the energy into heat. The conversion is
usually done by applying a contact material to the rotating wheels or to discs
attached to the axles. The material creates friction and converts the kinetic
energy into heat. The wheels slow down and eventually the train stops. The
material used for braking is normally in the form of a block or pad.

The vast majority of the world's trains are equipped with braking systems
which use compressed air as the force to push blocks on to wheels or pads
on to discs. These systems are known as "air brakes" or "pneumatic
brakes". The compressed air is transmitted along the train through a "brake
pipe". Changing the level of air pressure in the pipe causes a change in the
state of the brake on each vehicle. It can apply the brake, release it or hold it
"on" after a partial application. The system is in widespread use throughout
the world.

The Principal Parts of the Air Brake System
The diagram shows the principal parts of the air brake
system and these are described below.




Compressor
         The pump which draws air from atmosphere and
compresses it for use on the train. Its principal use is is for the air
brake system, although compressed air has a number of other uses
on trains. See Auxiliary Equipment.
Main Reservoir

      Storage tank for compressed air for braking and other pneumatic
systems.

Driver's Brake Valve

             The means by which the driver controls the brake. The brake
valve will have (at least) the following positions: "Release", "Running",
"Lap" and "Application" and "Emergency". There may also be a "Shut
Down" position, which locks the valve out of use.

The "Release" position connects the main reservoir to the brake pipe . This
raises the air pressure in the brake pipe as quickly as possible to get a rapid
release after the driver gets the signal to start the train.

In the "Running" position, the feed valve is selected. This allows a slow
feed to be maintained into the brake pipe to counteract any small leaks or
losses in the brake pipe, connections and hoses.

"Lap" is used to shut off the connection between the main reservoir and the
brake pipe and to close off the connection to atmosphere after a brake
application has been made. It can only be used to provide a partial
application. A partial release is not possible with the common forms of air
brake, particularly those used on US freight trains.
"Application" closes off the connection from the main reservoir and opens
the brake pipe to atmosphere. The brake pipe pressure is reduced as air
escapes. The driver (and any observer in the know) can often hear the air
escaping.

Most driver's brake valves were fitted with an "Emergency" position. Its
operation is the same as the "Application" position, except that the opening
to atmosphere is larger to give a quicker application.

Feed Valve

          To ensure that brake pipe pressure remains at the required level, a
feed valve is connected between the main reservoir and the brake pipe when
the "Running" position is selected. This valve is set to a specific operating
pressure. Different railways use different pressures but they generally range
between 65 and 90 psi (4.5 to 6.2 bar).

Equalising Reservoir

           This is a small pilot reservoir used to help the driver select the
right pressure in the brake pipe when making an application. When an
application is made, moving the brake valve handle to the application
position does not discharge the brake pipe directly, it lets air out of the
equalising reservoir. The equalising reservoir is connected to a relay valve
(called the "equalising discharge valve" and not shown in my diagram)
which detects the drop in pressure and automatically lets air escape from the
brake pipe until the pressure in the pipe is the same as that in the equalising
reservoir.

The equalising reservoir overcomes the difficulties which can result from a
long brake pipe. A long pipe will mean that small changes in pressure
selected by the driver to get a low rate of braking will not be seen on his
gauge until the change in pressure has stabilised along the whole train. The
equalising reservoir and associated relay valve allows the driver to select a
brake pipe pressure without having to wait for the actual pressure to settle
down along a long brake pipe before he gets an accurate reading.

Brake Pipe
 The pipe running the length of the train, which transmits the variations in
pressure required to control the brake on each vehicle. It is connected
between vehicles by flexible hoses, which can be uncoupled to allow
vehicles to be separated. The use of the air system makes the brake "fail
safe", i.e. loss of air in the brake pipe will cause the brake to apply. Brake
pipe pressure loss can be through a number of causes as follows:

      A controlled reduction of pressure by the driver
      A rapid reduction by the driver using the emergency position on his
       brake valve
      A rapid reduction by the conductor (guard) who has an emergency
       valve at his position
      A rapid reduction by passengers (on some railways) using an
       emergency system to open a valve
      A rapid reduction through a burst pipe or hose
      A rapid reduction when the hoses part as a result of the train
       becoming parted or derailed.

Angle Cocks

        At the ends of each vehicle, "angle cocks" are provided to allow the
ends of the brake pipe hoses to be sealed when the vehicle is uncoupled.
The cocks prevent the air being lost from the brake pipe.
Coupled Hoses

       The brake pipe is carried between adjacent vehicles through flexible
hoses. The hoses can be sealed at the outer ends of the train by closing the
angle cocks.

Brake Cylinder

         Each vehicle has at least one brake cylinder. Sometimes two or
more are provided. The movement of the piston contained inside the
cylinder operates the brakes through links called "rigging". The rigging
applies the blocks to the wheels. Some modern systems use disc brakes.
The piston inside the brake cylinder moves in accordance with the change in
air pressure in the cylinder.

Auxiliary Reservoir

       The operation of the air brake on each vehicle relies on the difference
in pressure between one side of the triple valve piston and the other. In
order to ensure there is always a source of air available to operate the brake,
an "auxiliary reservoir" is connected to one side of the piston by way of the
triple valve. The flow of air into and out of the auxiliary reservoir is
controlled by the triple valve.

Brake Block

       This is the friction material which is pressed against the surface of the
wheel tread by the upward movement of the brake cylinder piston. Often
made of cast iron or some composition material, brake blocks are the main
source of wear in the brake system and require regular inspection to see that
they are changed when required.

Many modern braking systems use air operated disc brakes. These operate to
the same principles as those used on road vehicles.

Brake Rigging

        This is the system by which the movement of the brake cylinder
piston transmits pressure to the brake blocks on each wheel. Rigging can
often be complex, especially under a passenger car with two blocks to each
wheel, making a total of sixteen. Rigging requires careful adjustment to
ensure all the blocks operated from one cylinder provide an even rate of
application to each wheel. If you change one block, you have to check and
adjust all the blocks on that axle.

Triple Valve

         The operation of the brake on each vehicle is controlled by the
"triple valve", so called because it originally comprised three valves - a
"slide valve", incorporating a "graduating valve" and a "regulating valve". It
also has functions - to release the brake, to apply it and to hold it at the
current level of application. The triple valve contains a slide valve which
detects changes in the brake pipe pressure and rearranges the connections
inside the valve accordingly. It either:

      recharges the auxiliary reservoir and opens the brake cylinder exhaust,
      closes the brake cylinder exhaust and allows the auxiliary reservoir air
       to feed into the brake cylinder
      or holds the air pressures in the auxiliary reservoir and brake cylinder
       at the current level.

The triple valve is now usually replaced by a distributor - a more
sophisticated version with built-in refinements like graduated release.

OPERATION ON EACH VEHICLE
Brake Release

This diagram shows the condition of the brake cylinder, triple valve and
auxiliary reservoir in the brake release position.
          The driver has placed the brake valve in the "Release" position.
Pressure in the brake pipe is rising and enters the triple valve on each car,
pushing the slide valve provided inside the triple valve to the left. The
movement of the slide valve allows a "feed groove" above it to open
between the brake pipe and the auxiliary reservoir, and another connection
below it to open between the brake cylinder and an exhaust port. The feed
groove allows brake pipe air pressure to enter the auxiliary reservoir and it
will recharge it until its pressure is the same as that in the brake pipe. At the
same time, the connection at the bottom of the slide valve will allow any air
pressure in the brake cylinder to escape through the exhaust port to
atmosphere. As the air escapes, the spring in the cylinder will push the
piston back and cause the brake blocks to be removed from contact with the
wheels. The train brakes are now released and the auxiliary reservoirs are
being replenished ready for another brake application.

Brake Application

This diagram (left) shows the condition of the brake cylinder, triple valve
and auxiliary reservoir in the brake application position.




          The driver has placed the brake valve in the "Application"
position. This causes air pressure in the brake pipe to escape. The loss of
pressure is detected by the slide valve in the triple valve. Because the
pressure on one side (the brake pipe side) of the valve has fallen, the
auxiliary reservoir pressure on the other side has pushed the valve (towards
the right) so that the feed groove over the valve is closed. The connection
between the brake cylinder and the exhaust underneath the slide valve has
also been closed. At the same time a connection between the auxiliary
reservoir and the brake cylinder has been opened. Auxiliary reservoir air
now feeds through into the brake cylinder. The air pressure forces the piston
to move against the spring pressure and causes the brake blocks to be
applied to the wheels. Air will continue to pass from the auxiliary reservoir
to the brake cylinder until the pressure in both is equal. This is the
maximum pressure the brake cylinder will obtain and is equivalent to a full
application. To get a full application with a reasonable volume of air, the
volume of the brake cylinder is usually about 40% of that of the auxiliary
reservoir.

Lap

The purpose of the "Lap" position is to allow the brake rate to be held
constant after a partial application has been made.




           When the driver places the brake valve in the "Lap" position while
air is escaping from the brake pipe, the escape is suspended. The brake pipe
pressure stops falling. In each triple valve, the suspension of this loss of
brake pipe pressure is detected by the slide valve because the auxiliary
pressure on the opposite side continues to fall while the brake pipe pressure
stops falling. The slide valve therefore moves towards the auxiliary
reservoir until the connection to the brake cylinder is closed off. The slide
valve is now half-way between its application and release positions and the
air pressures are now is a state of balance between the auxiliary reservoir
and the brake pipe. The brake cylinder is held constant while the port
connection in the triple valve remains closed. The brake is "lapped".

Lap does not work after a release has been initiated. Once the brake valve
has been placed in the "Release" position, the slide valves will all be moved
to enable the recharge of the auxiliary reservoirs. Another application
should not be made until sufficient time has been allowed for this recharge.
The length of time will depend on the amount of air used for the previous
application and the length of the train.



                          Emergency Air Brake
        Most air brake systems have an "Emergency" position on the driver's
brake valve. This position dumps the brake pipe air quickly. Although the
maximum amount of air which can be obtained in the brake cylinders does
not vary on a standard air brake system, the rate of application is faster in
"Emergency". Some triple valves are fitted with sensor valves which detect
a sudden drop in brake pipe pressure and then locally drop brake pipe
pressure. This has the effect of speeding up the drop in pressure along the
train - it increases the "propagation rate".

Emergency Reservoirs

       Some air brake systems use emergency reservoirs. These are
provided on each car like the auxiliary reservoir and are recharged from the
brake pipe in a similar way. However, they are only used in an emergency,
usually being triggered by the triple valve sensing a sudden drop in brake
pipe pressure. A special version of the triple valve (a distributor) is required
for cars fitted with emergency reservoirs.

Distributors

       A distributor performs the same function as the triple valve, it's just a
more sophisticated version. Distributors have the ability to connect an
emergency reservoir to the brake system on the vehicle and to recharge it.
Distributors may also have a partial release facility, something not usually
available with triple valves.

A modern distributor will have:

      a quick service feature - where a small chamber inside the distributor
       is used to accept brake pipe air to assist in the transmission of pressure
       reduction down the train
      a reapplication feature - allowing the brake to be quickly re-applied
       after a partial release
      a graduated release feature - allowing a partial release followed by a
       holding of the lower application rate
      a connection for a variable load valve - allowing brake cylinder
       pressure to adjust to the weight of the vehicle
      chokes (which can be changed) to allow variations in brake
       application and release times
      an inshot feature - to give an initial quick application to get the blocks
       on the wheels
      brake cylinder pressure limiting
      auxiliary reservoir overcharging prevention.




All of these features are achieved with no electrical control. The control
systems comprise diaphragms and springs arranged in a series of complex
valves and passages within the steel valve block. Distributors with all these
features will normally be provided on passenger trains or specialist high-
speed freight vehicles.
Two Pipe Systems

          A problem with the design of the standard air brake is that it is
possible to use up the air in the auxiliary reservoir more quickly than the
brake pipe can recharge it. Many runaways have resulted from overuse of
the air brake so that no auxiliary reservoir air is available for the much
needed last application. Read Al Krug's paper North American Freight
Train Brakes for a detailed description of how this happens. The problem
can be overcome with a two-pipe system as shown in the simplified diagram
below.




          The second pipe of the two-pipe system is the main reservoir pipe.
This is simply a supply pipe running the length of the train which is fed from
the compressor and main reservoir. It performs no control function but it is
used to overcome the problem of critical loss of pressure in the auxiliary
reservoirs on each car. A connecting pipe, with a one-way valve, is
provided between the main reservoir pipe and the auxiliary reservoir. The
one-way valve allows air from the main reservoir pipe to top up the auxiliary
reservoir. The one-way feature of the valve prevents a loss of auxiliary
reservoir air if the main reservoir pressure is lost.

Another advantage of the two-pipe system is its ability to provide a quick
release. Because the recharging of the auxiliaries is done by the main
reservoir pipe, the brake pipe pressure increase which signals a brake release
is used just to trigger the brake release on each car, instead of having to
supply the auxiliaries as well.

Two pipe systems have distributors in place of triple valves. One feature of
the distributor is that it is designed to restrict the brake cylinder pressure so
that, while enough air is available to provide a full brake application, there
isn't so much that the brake cylinder pressure causes the blocks to lock the
wheels and cause a skid. This is an essential feature if the auxiliary reservoir
is being topped up with main reservoir air, which is usually kept at a higher
pressure than brake pipe air.

Needless to say, fitting a second pipe to every railway vehicle is an
expensive business so it is always the aim of the brake equipment designer
to allow backward compatibility - in much the same way as new computer
programs are usually compatible with older versions. Most vehicles fitted
with distributors or two-pipe systems can be operated in trains with simple
one-pipe systems and triple valves, subject to the correct set-up during train
formation.

Self Lapping Brake Valves

Self lapping is the name given to a brake controller which is position
sensitive, i.e. the amount of application depends on the position of the brake
valve handle between full release and full application. The closer the brake
handle is to full application, the greater the application achieved on the
train. The brake valve is fitted with a pressure sensitive valve which allows
a reduction in brake pipe pressure according to the position of the brake
valve handle selected by the driver. This type of brake control is popular on
passenger locomotives.

Other Air Operated Equipment

       On an air braked train, the compressed air supply is used to provide
power for certain other functions besides braking. These include door
operation, whistles/horns, traction equipment, pantograph operation and rail
sanders.

BOGIE MOUNTED BRAKE GEAR

GENERAL
In order t of slack adjuster failure as well as problemsassociated with cast
iron brake blocks, adesign of brake system incorporating 8"size two
cylinders on each bogie alongwith ‘K’ type high friction compositebrake
blocks has been introduced.

DESIGN FEATURES OF THESYSTEM
 This type of system is exactly similar tothe standard air brake system except
forthe following:


Four cylinder of 8" size is providedfor each coach in place of twocylinders
of
14"
in standard air brake system. These cylinders havebuilt in single acting slack
adjusterfor taking the slack created betweenwheel and brake block on
account of wheel / brake block wear. Mountingof cylinders is done on either
side of the bogie frame in between centrallongitudinal members connecting
thebogie transom to the headstocks.Each cylinder controls the brakingon one
wheel set. Each cylinder hasa piston take up stroke of
32 mm
andadjustment capacity of
305 mm

High friction composite brake blocksof ‘K’ type have been used.d)

Bogie brake rigging has beenmodified to incorporate a totalmechanical
advantage of
7.644 perbogie
for non-AC coaches and
8.40per bogi
e for AC coaches.
Curved profile pull rods have beenused to interconnect leverscontrolling
braking one wheel set.These pull rods provided with oneadditional hole for
the adjustment of slack between wheel and block afterspecified amount of
wear.f)

Since brake cylinders have beenmounted on the bogie frame, 15mm.bore
pneumatic pipeline has beenlaid over bogie frame to interconnect the brake
cylinders of onebogie. Output pipe line of distributorvalve has been
connected to bogiepneumatic line through flexiblehoses to provide
flexibility toalround dynamic movement.603
COMPOSITE BRAKE BLOCK

General
Low friction composite brake blockshave the following benefits:
Reduced braking distance due touniform co-efficient of friction.
Reduced weight
Reduction in the replacement of brake blocks vis a vis cast iron due tohigher
wear life in train operation.
Reduced wear and tear of brakerigging. Reduced noise during braking.
Characteristics of composition brakeblocks
Composition of material
The composition of materialconstituting the brake blocks must bechosen to
give the best balancebetween :
The braking characteristics
The wear and service life of blocks
Wear on the running surface of thewheels
The effect on adhesion between therail and wheel
Requirement concerning friction
  REQUIRED
MACHINES FOR
MACHINE SHOP
& WHEEL SHOP
                       INTRODUCTION:
In Izatnagar Railway N.E. mechanical workshop are mostly
common maschines are used in the operations of machine and
wheel shops. Some operations of machine shop are operated in
the wheel shop and vice versa.
The work of machine shop is to machine the parts required for
POH work as per drawing and instruction.
In this shop mass removel process are executed with the help of
different types of machines

These machines perform following operations during the POH
of locomotives and coaches in the IZATNAGAR RAILWAY
WORKSHOP with the use of many types of machines.

                   Types of machining operation
There are many kinds of machining operations, each of which is capable
of generating a certain part geometry and surface texture.

Turning
 A cutting tool with a single cutting edge is used to remove material
from a rotating workpiece to generate a cylindrical shape. The speed
motion in turning is provided by the rotating workpart, and the feed
motion is achieved by the cutting tool moving slowly in a direction
parallel to the axis of rotation of the workpiece

operations are operations that rotate the workpiece as the primary
method of moving metal against the cutting tool. Lathes are the
principal machine tool used in turning.

Drilling
It is used to create a round hole. It is accomplished by a rotating tool
that is typically has two or four cutting edges. The tool is fed in a
direction parallel to its axis of rotation into the workpart to form the
round hole.
Boring
 The tool is used to enlarge an already available hole. It is a fine
finishing operation used in the final stages of product manufacture.

Milling
A rotating tool with multiple cutting edges is moved slowly relative to
the material to generate a plane or straight surface. The direction of the
feed motion is perpendicular to the tool's axis of rotation. The speed
motion is provided by the rotating milling cutter. The two basic forms
of milling are:

     Peripheral milling
     Face milling

Knurling




Knurling is a manufacturing process, typically conducted on a lathe,
whereby a visually attractive diamond-shaped (criss-cross) pattern is
cut or rolled into metal. This pattern allows hands or fingers to get a
better grip on the knurled object than would be provided by the
originally smooth metal surface. Occasionally, the knurled pattern is a
series of straight ridges or a helix of "straight" ridges rather than the
more-usual criss-cross pattern.
Knurling may also be used as a repair method: because a rolled-in
knurled surface has raised-up areas surrounding the depressed areas,
these raised areas can make up for wear on the part. In the days when
labor was cheap and parts expensive, this repair method was feasible on
pistons of internal combustion engines, where the skirt of a worn piston
was expanded back to the nominal size using a knurling process. As
auto parts have become less expensive, knurling has become less
prevalent than it once was, and is specifically recommended against by
performance engine builders.[1]

Knurling can also be used when a high precision component will be
assembled into a low precision component, for example a metal pin into
a plastic molding. The outer surface of the metal pin is knurled so that
the raised detail 'bites' into the plastic irrespective of whether the size of
the hole in the plastic closely matches the diameter of the pin.




Chamfering
Chamfering is part of the process of hand-crafting a parabolic
glass telescope mirror. Before the surface of the disc can be
ground, the edges must first be chamfered to prevent chipping.
This can be accomplished by placing the disc in a metal bowl
containing silicon carbide and rotating the disc with a rocking
motion. The grit will thus wear off the sharp edge of the glass.

Grinding
Grinding is an abrasive machining process that uses a grinding wheel as
the cutting tool



Facing
A lathe can be used to create a smooth, flat, face very accurately
perpendicular to the axis of a cylindrical part. First, clamp the part
securely in a lathe chuck. Then, install a facing tool. Bring the tool
approximately into position, but slightly off of the part. Always turn the
spindle . before turning it on. This ensures that no parts interfere with
the rotation of the spindle. Move the tool outside the part and adjust the
saddle to take the desired depth of cut. Then, feed the tool across the
face with the cross slide. The following clip shows a roughing cut being
made; about 50 thousandths are being removed in one pass. If a finer
finish is required, take just a few thousandths on the final cut and use
the power feed. Be careful clearing the ribbon-like chips; They are very
sharp. Do not clear the chips while the spindle is turning. After facing,
there is a very sharp edge on the part. Break the edge (205kB) with a
file.

Parting
A parting tool is deeper and narrower than a turning tool. It is designed
for making narrow grooves and for cutting off parts. When a parting
tool is installed, ensure that it hangs over the tool holder enough that the
the holder will clear the workpiece (but no more than that). Ensure that
the parting tool is perpendicular to the axis of rotation and that the tip
is the same height as the center of the part. A good way to do this is to
hold the tool against the face of the part. Set the height of the tool, lay it
flat against the face of the part, then lock the tool in place. When the cut
is deep, the side of the part can rub against sides of the groove, so it's
especially important to apply cutting fluid. In this clip, a part is cut off
from a piece of stock.


Treading & Chasing:
Taps and dies are cutting tools used to create screw threads, which is
called threading. A tap is used to cut the female portion of the mating
pair (e.g., a nut). A die is used to cut the male portion of the mating pair
(e.g., a screw). The process of cutting threads using a tap is called
tapping, whereas the process using a die is called threading. Both tools
can be used to clean up a thread, which is called chasing.




Cutting tool
.




    Different machines used in Machine shop & Wheel shop are:

    1. Radial drill machinE
    2. Centre lathe machine
    3. Horizontal Boring machine
    4. Vertical boring machine
    5. Horizontal milling machine
    6. Vertical milling machine
    7. Slotting machine
    8. Capstan lathe
    9. Turret lathe
    10.Different types of CNC machines
    11.Wheel turning lathe
    12.Wheel axle lathe
    13.CNC turning centre
    14.Combination lathe machine
    15.Wheel lathe
    16.Brake lathe etc…..
Lathe (metal)




Center lathe with DRO and chuck guard. Size is 460 mm swing x
1000 mm between centers




A metal lathe or metalworking lathe is a large class of lathes designed
for precisely machining relatively hard materials. They were originally
designed to machine metals; however, with the advent of plastics and
other materials, and with their inherent versatility, they are used in a
wide range of applications, and a broad range of materials. In
machining jargon, where the larger context is already understood, they
are usually simply called lathes, or else referred to by more-specific
subtype names (toolroom lathe, turret lathe, etc.). These rigid machine
tools remove material from a rotating workpiece via the (typically
linear) movements of various cutting tools, such as tool bits and drill
bits




Parts of lathe machine are:




                           Drilling Machine:
Drilling Machine is somewhat special purpose machine and somewhat
general purpose machine. I am calling it special purpose machine
because it is used for drilling related operation and general purpose
because it can perform many operations like that of driPrinciple of
Drilling Machine
Parts of Drilling Machine:
There are various kinds of Drilling Machine depending on their use.

  1.   Drilling Head.
  2.   Feeding Mechanism.
  3.   Supporting Column.
  4.   Chuck or Tool Holder.
  5.   Drive Mechanism.
  6. Work Table with Tee Slots.

Types of Drilling Machine:
Here are some kinds of drilling machines.

      Sensitive Drilling Machine.
      Upright Drilling Machine.
      Radial Drilling Machine.
      Multiple Spindles Drilling Machine.
      Deep Hole Drilling Machine.
      Portable Drilling Machine.
      Automatic Drilling Machine.




Operations Performed on Drilling Machine:
Drilling Machine can perform various machining operations which are
related to drilling.

  1.   Drilling.
  2.   Tapping.
  3.   Reaming.
  4.   Counter Sinking.
  5.   Counter Boring.
  6.   Boring.
  7.   Tee Slot Cutting.
  8.   Grinding.
CNC lathe / CNC turning center:
Its machine is mainly used in wheel shop for turning of wheel
profil in Izatnagar workshop.




CNC lathe with milling capabilities




An example turned vase and view of the tool turret

CNC lathes are rapidly replacing the older production lathes
(multispindle, etc.) due to their ease of setting and operation. They are
designed to use modern carbide tooling and fully use modern processes.
The part may be designed and the toolpaths programmed by the
CAD/CAM process, and the resulting file uploaded to the machine, and
once set and trialled the machine will continue to turn out parts under
the occasional supervision of an operator.

The machine is controlled electronically via a computer menu style
interface, the program may be modified and displayed at the machine,
along with a simulated view of the process. The setter/operator needs a
high level of skill to perform the process, however the knowledge base is
broader compared to the older production machines where intimate
knowledge of each machine was considered essential. These machines
are often set and operated by the same person, where the operator will
supervise a small number of machines (cell).

The design of a CNC lathe has parts are still recognizable, the turret
holds the tools and indexes them as needed. The machines are often
totally enclosed, due in large part to Occupational health and safety
(OH&S) issues.

With the advent of cheap computers, free operating systems such as
Linux, and open source CNC software, the entry price of CNC
machines has plummeted.

Swiss-style lathe / Swiss turning center




A view inside the enclosure of a CNC Swiss-style lathe/screw machine.

For work requiring extreme accuracy (sometimes holding tolerances as
small as a few tenths of a thousandth of an inch), a Swiss-style lathe is
often used. A Swiss-style lathe holds the workpiece with both a collet
and a guide bushing. The collet sits behind the guide bushing, and the
tools sit in front of the guide bushing, holding stationary on the Z axis.
To cut lengthwise along the part, the tools will move in and the material
itself will move back and forth along the Z axis. This allows all the work
to be done on the material near the guide bushing where it is more rigid,
making them ideal for working on slender workpieces as the part is held
firmly with little chance of deflection or vibration occurring.

This style of lathe is also available with CNC controllers to further
increase its versatility.

Most CNC Swiss-style lathes today use one or two main spindles plus
one or two back spindles (secondary spindles). The main spindle is used
with the guide bushing for the main machining operations. The
secondary spindle is located behind the part, aligned on the Z axis. In
simple operation it picks up the part as it is cut off (aka parted off) and
accepts it for second operations, then ejects it into a bin, eliminating the
need to have an operator manually change each part, as is often the case
with standard CNC turning centers. This makes them very efficient, as
these machines are capable of fast cycle times, producing simple parts in
one cycle (i.e. no need for a second machine to finish the part with
second operations), in as little as 10–15 seconds. This makes them ideal
for large production runs of small-diameter parts.

Additionally, as many Swiss lathes incorporate a secondary spindle, or
'sub-spindle', they also incorporate 'live tooling'. Live tools are rotary
cutting tools that are powered by a small motor independently of the
spindle motor(s). Live tools increase the intricacy of components that
can be manufactured by the Swiss lathe. For instance, automatically
producing a part with a hole drilled perpendicular to the main axis (the
axis of rotation of the spindles) is very economical with live tooling, and
similarly uneconomical if done as a 'secondary operation' after
machining by the Swiss lathe is complete. A 'Secondary operation' is a
machining operation requiring a partially completed part to be secured
in a second machine to complete the manufacturing process. Generally,
advanced CAD/CAM software uses live tools in addition to the main
spindles so that most parts that can be drawn by a CAD system can
actually be manufactured by the machines that the CAD/CAM software
support.
Combination lathe / 3-in-1 machine
A combination lathe, often known as a 3-in-1 machine, introduces
drilling or milling operations into the design of the lathe. These
machines have a milling column rising up above the lathe bed, and they
utilize the carriage and topslide as the X and Y axes for the milling
column. The 3-in-1 name comes from the idea of having a lathe, milling
machine, and drill press all in one affordable machine tool. These are
exclusive to the hobbyist and MRO markets, as they inevitably involve
compromises in size, features, rigidity, and precision in order to remain
affordable. Nevertheless, they meet the demand of their niche quite well,
and are capable of high accuracy given enough time and skill. They may
be found in smaller, non-machine-oriented businesses where the
occasional small part must be machined, especially where the exacting
tolerances of expensive toolroom machines, besides being unaffordable,
would be overkill for the application anyway from an engineering
perspective.

Mini-lathe and micro-lathe
Mini-lathes and micro-lathes are miniature versions of a general-
purpose center lathe (engine lathe). They typically have swings in the
range of 3" to 7" (70 mm to 170 mm) diameter (in other words, 1.5" to
3.5" (30 mm to 80 mm) radius). They are small and affordable lathes
for the home workshop or MRO shop. The same advantages and
disadvantages apply to these machines as explained earlier regarding 3-
in-1 machines.

As found elsewhere in English-language orthography, there is variation
in the styling of the prefixes in these machines' names. They are
alternately styled as mini lathe, minilathe, and mini-lathe and as micro
lathe, microlathe, and micro-lathe.

Wheel lathe
A lathe for turning the wheels of railway locomotives and rolling stock.
Brake lathe
A lathe specialized for the task of resurfacing brake drums and discs in
automotive or truck garages.
CARRIAGE WORKS
 IN IZATNAGAR
   WORKSHOP
CARRIAGE WORKS:

Following carriage works are operated under the carriage shop
     1:Inspection
     2:Corrosion
     3:Furnishing
     4:Paintig
     5:Braking System

                             1:Inspection
       The Indian Railways serve as the principal mode of passenger
transport in the country. It therefore, needs well maintained coaching
stock for transportation of coaching traffic efficiently, safely and
punctually. The productivity of a network like that of the Railways
depends, to a large measure, on its fleet of coaches being well
maintained. An effective and efficient coach maintenance system should
have timely preventive maintenance to avoid occurrence of predictable
defects, apart from attending to repairs promptly, so as to keep the
coaches fit for traffic and to provide the desired riding quality,
passenger comfort and safe running condition. Further, detention of
rolling stock for maintenance should be kept to the barest minimum.

All Passenger Coaching Vehicles (PCVs) owned by individual Railways,
are allotted by the Chief Mechanical Engineer to a base depot for
primary maintenance and a base workshop for periodical overhaul
(POH) and special repairs. As the basic maintenance of coaches is done
in workshops during POH, special efforts are necessary to ensure good
workmanship and to assure quality of repair during POH in workshop
so that the coaches give reliable service on line.


                             2:Corrosion
Corrosion is the disintegration of an engineered material into its
constituent atoms due to chemical reactions with its surroundings. In
the most common use of the word, this means electrochemical oxidation
of metals in reaction with an oxidant such as oxygen. Formation of an
oxide of iron due to

oxidation of the iron atoms in solid solution is a well-known example of
electrochemical corrosion, commonly known as rusting. This type of
damage typically produces oxide(s) and/or salt(s) of the original metal.
Corrosion can also refer to other materials than metals, such as
ceramics or polymers, although in this context, the term degradation is
more common.

In other words, corrosion is the wearing away of metals due to a
chemical reaction.

Many structural alloys corrode merely from exposure to moisture in the
air, but the process can be strongly affected by exposure to certain
substances (see below). Corrosion can be concentrated locally to form a
pit or crack, or it can extend across a wide area more or less uniformly
corroding the surface. Because corrosion is a diffusion controlled
process, it occurs on exposed surfaces. As a result, methods to reduce
the activity of the exposed surface, such as passivation and chromate-
conversion, can increase a material's corrosion resistance. However,
some corrosion mechanisms are less visible and less predictable.




Rust, the most familiar example of corrosion.




                    CORROSION IN RAILWAY
The most common form of corrosion of rails is atmos-pheric corrosion,
resulting from the wetting and drying process. The atmospheric
corrosion of rails results in uni-form corrosion. Corrosion will be more
severe for longer moisture residence time and frequent wetting and
drying. Uniform corrosion will be aggravated in the presence of
chloride ions, because they destabilize the protective rusts on the surface
9 . For this reason, rails laid near coastal re-gions are more prone to
atmospheric corrosion, warrant-ing more frequent replacement than
rails in a dry climate. Of far more importance, from both economic and
safety perspectives, is the enhanced corrosion that takes place at certain
localized locations. There are two origins for the occurrence of localized
corrosion in Indian rails. The first cause is due to leakage of current in
electri-fied railway systems 10 . Intense corrosion attack take life of C–
Mn steel-based rail to nearly half its expected life 2 (A. Jain and P.
Funkwal, unpublished). An analysis of rail renewal in India for 2006–
2007 (A. Jain and P. Funkwal, unpublished) indicates that only 32% of
the replacement of rails took place after completion of normal expected
life of the rails. Data show that 37% of the rails undergo replacement
due to corrosion before their estimated service life, whereas only 16% of
the rail replacement is due to wear and 15% due to rail-weld fail-ure (A.
Jain and P. Funkwal, unpublished). Modern rails are normally
eutectoid steels, i.e. high carbon steels containing about 0.70–0.80 wt%
carbon. These steels possess a fully pearlitic microstructure, which
provides a good combination of strength, hardness and ductility.
However, the presence of a high amount of cementite in pearlite renders
the structure susceptible to corrosion 3 . This article highlights the
recent rail steel development activities focused on corrosion prevention
of rails for the Indian railways, undertaken as a academia–industry–
user (IIT Kanpur–Steel Authority of India (SAIL)–Indian Railways)
collaborative research programme, to develop a novel rail steel of
relatively improved corrosion per-formance than the standard rail steel
currently in use. Under the aegis of the Technology Mission for Railway
Safety (TMRS), initiated by the Ministry of Railways, the three
institutions were brought together to find a solution to the acute
corrosion problem faced by Indian Railways. The research team from
IIT Kanpur was instrumental in planning the rail steel compositions
and was responsible for carrying out experimental studies. The work
was completed with additional efforts put together by the industrial
partner, Bhilai Steel Plant (SAIL), which was responsible for
manufacturing the rail steel plates on an experimental basis as well as
manufacturing the actual novel corrosion-resistant rail. In this context,
the different forms of corrosion that are noted

in rails and the rail fastening system, especially under Indian conditions,
will be first considered in this article. rovidedSome relevant
experimental details related to corrosion performance of actual rail
samples will also be p.


                    TYPES OF CORROSION
1:Galvanic corrosion
Galvanic corrosion occurs when two different metals electrically contact
each other and are immersed in an electrolyte. In order for galvanic
corrosion to occur, an electrically conductive path and an ionically
conductive path are necessary. This effects a galvanic couple where the
more active metal corrodes at an accelerated rate and the more noble
metal corrodes at a retarded rate. When immersed, neither metal would
normally corrode as quickly without the electrically conductive
connection (usually via a wire or direct contact). Galvanic corrosion is
often utilized in sacrificial anode. What type of metal(s) to use is readily
determined by following the galvanic series. For example, zinc is often
used as a sacrificial anode for steel structures, such as pipelines or
docked naval ships. Galvanic corrosion is of major interest to the
marine industry and also anywhere water can contact p] Pitting
corrosion




2:Pitting corrosion
The scheme of pitting corrosion
Certain conditions, such as low concentrations of oxygen or
high concentrations of species such as chloride which compete
as anions, can interfere with a given alloy's ability to re-form a
passivating film. In the worst case, almost all of the surface will
remain protected, but tiny local fluctuations will degrade the
oxide film in a few critical points. Corrosion at these points will
be greatly amplified, and can cause corrosion pits of several
types, depending upon conditions. While the corrosion pits
only nucleate under fairly extreme circumstances, they can
continue to grow even when conditions return to normal, since
the interior of a pit is naturally deprived of oxygen and locally
the pH decreases to very low values and the corrosion rate
increases due to an auto-catalytic process. In extreme cases, the
sharp tips of extremely long and narrow corrosion pits can
cause stress concentration to the point that otherwise tough
alloys can shatter; a thin film pierced by an invisibly small hole
can hide a thumb sized pit from view. These problems are
especially dangerous because they are difficult to detect before
a part or structure fails. Pitting remains among the most
common and damaging forms of corrosion in passivated alloys,
but it can be prevented by control of the alloy's environment.
.



3:Microbial corrosion
Microbial corrosion, or bacterial corrosion, is a corrosion caused or
promoted by microorganisms, usually chemoautotrophs. It can apply to
both metals and non-metallic materials, in both the presence and lack of
oxygen. Sulfate-reducing bacteria are common in lack of oxygen; they
produce hydrogen sulfide, causing sulfide stress cracking. In presence of
oxygen, some bacteria directly oxidize iron to iron oxides and
hydroxides, other bacteria oxidize sulfur and produce sulfuric acid
causing biogenic sulfide corrosion. Concentration cells can form in the
deposits of corrosion products, causing and enhancing galvanic
corrosion.

Accelerated Low Water Corrosion (ALWC) is a particularly aggressive
form of MIC that affects steel piles in seawater near the low water tide
mark. It is characterised by an orange sludge, which smells of Hydrogen
Sulphide when treated with acid. Corrosion rates can be very high and
design corrosion allowances can soon be exceeded leading to premature
failure of the steel pile.[1] Piles that have been coating and have cathodic
protection installed at the time of construction are not susceptible to
ALWC. For unprotected piles sacrificial anodes can be installed local to
the affected areas to inhibit the corrosion or a complete retrofitted
sacrificial anode system can be installed. Affected areas can also be
treated electrochemically by using an electrode to first produce chlorine
to kill the bacteria, and then to produced a calcareous deposit, which
will help shield the metal from further attack.

                              3:Furnishing

Furnishing is the process of decoration of different passenger using
acceceries in the bogies.
Changing the sheets, fans, washers , etc. during POH of trains is called
furnishing process.

      Decorative Laminated Sheet
      PVC Flooring
      Rexine for Berths


Ironically , in the decision taken for increased periodicity, it was also
decided that the Bogie shall be sent by the divisions to the Repair
Workshops every 9 months. Earlier the coaches along wih the bogie
was comming to the workshop for POH when the material used was not
yet upgraded. However, with th introduction of upgraded material in
the bogie, the POH/ IOH i.e maimtainance required at the repair
Workshops should have increased beyond 12 moths . However, inspite
of introduction of upgraded material, the maintainance requirement of
the bogie has been reduced to 9 months , much lower than the 12
months which was earlier the case when non upgraded material was
bieng used.

Why should a bogie com for IOH in the eworkshop in 9 months which
has upgraded material which is supposed to last for 2 POH cycles i.e 36
months.


                                4:Paintig

Painting is the important part of carriage shop during overhauling
period. Painting is done mainly in the shell portion of the coaches. B.G.
coach is required more painting works then other types of coaches.
Its prevents the material from corrosion and used for decorates the rail
components.
                           5:Braking System
Brakes are used on the cars of railway trains to enable deceleration,
control acceleration (downhill) or to keep them standing when parked.
While the basic principle is familiar from road vehicle usage,
operational features are more complex because of the need to control
multiple linked carriages and to be effective on vehicles left without a
prime mover. Clasp brakes are one type of brakes historically used on
trains.
During overhauling period defected braking system equipments are
replaced and coated by anticorrosive materials.

				
DOCUMENT INFO
Shared By:
Tags:
Stats:
views:112
posted:8/4/2012
language:
pages:53