Introduction, history, components, function and limitations of railway air brakes system

1. GOVERNMENT POLYTECHNIC, THANE
AIR BRAKES SYSTEM OF RAILWAY
Presented by:SHRADDHA MAHABARE
Roll no:32
Class:ME5GF (M2)

2. Introduction
 The most vital factor in the running and control of
any vehicle whether it is a cycle. scooter, car. bus, or
train is the breaking system. In order slow down the
moving vehicle in a shorter possible time, the energy
of motion possessed by vehicle must be converted
in to other forms. During break application in any
vehicle the energy of motion is converted in to heat
This u might have noticed at the rim when you apply
brakes repeatedly at short intervals.

3. Literature Review
 Modern trains rely upon a fail-safe air brake
system that is based upon a design patented
by George Westinghouseon March 5

4. Air brake system of Railway
 Air brakes system :In air brake system compressed
air is used for operating the brake system. The
locomotive compressor charges the pipe
throughout the length of the train. It consists of
many parts such auxiliary reservoir, distributor
valve, isolating cock, angle cock, etc. Brake
Application takes place by dropping the brake
pressure in the brake pipe. For application of
brakes, driver moves the handle of A-9 valve in the
application position. By this movement the brake
pipe pressure is reduced which is sensed by
distributor valve to operate brake cylinder

5.  (1). Pneumatic pressure in the brake cylinder
causes piston assembly (2) to move outward
thereby causing lever (3) to rotate about its
fulcrum (a) thus bringing brake block (4) to
come in contact with the wheel (5) through the
brake beam (6). Since lever (3) is hung on the
bogie frame through lever hangers, it will start
moving forward about fulcrum (b) after brake
block (4) has contacted wheel (5). This forward
motion of the lever (3) about fulcrum (b) will
cause pull rod (7) to move forward thereby
causing lever (8) to swing about fulcrum (c) and
hence resulting in contact of brake block (9)
against wheel (5) through brake beam (10).

6.  Earlier vacuum
brake system was
used but as it got
certain
disadvantage this
system got
rejected such as

7.  In air brake system there is two types of system
 Twin pipe system
 Single pipe system

8. Components
 Distributor valve. It’s the heart of the system. BP pressure enters
into it and get stored in CR as CR pressure. It as common pipe
bracket so 3 pipe that is AR, BP, BC are connected to it. When BP
pressure decreases CR gets and it starts moving and the hollow
tube which connect to diaphragm gets lifted up. The tube has a seal
in AR chamber which gets open up and compressed air moves into
BC. When BP pressure is increased it balances CR which comes to
original position and excess air moves out from hollow tube to
atmosphere.
Auxiliary reservoir : An auxiliary reservoir of 200 liters is
provided on each wagon to store compressed air. It is charged to
6 Kg/cm2 through the feed pipe. The auxiliary reservoir is made
out of sheet metal. On both the ends of the reservoir, flanges are
provided for pipe connection. When BP pressure decreases AR
pressure moves in brake cylinder as BC pressure

9.  Cut-Off Angle Cock :Cut off angle cocks are provided at the ends
of brake pipe / feed pipe on each wagon. These cocks are closed at
the time of uncoupling of wagons. The vent provided in the cock
facilitates easy uncoupling of hose coupling by venting the air
trapped in the hose coupling when the cock is closed. The handle
of angle cock is spring loaded having a self locking type of
arrangement to avoid any inadvertent movement from open to
close position or vice versa.
 Hose Coupling :The hose couplings are provided to connect brake
pipeline & feed pipe line throughout the train. It consists of rubber
hose connected to coupling head and nipple by "Band it" type of
clamps. The nipple goes into the angle cock and the coupling
heads are coupled together. Rubber gasket is used in the coupling
head to make the joint leak proof . The End of the hose are painted
with green and white color, the green color indicates the brake
pipe and the white color indicates the feed pipe. The hose are
coupled by palm coupling throughout the train..

10.  Dirt Collector :Dirt collector is provided at the
junction of the main brake pipe and branch pipe. This is
meant for removing dust from the air prior to entering
the distributor valve. This is achieved by centrifugal
action. Their is filter inside the dirt collector which
collects the dust particles and it is replaced at the time
of every POH. The sealing plate and the gasket is also
replaced if found in damage condition.
 Isolating Cock Isolating cock without vent is provided
in the FP line of the twin pipe wagons. The isolating
cock is used to isolate the FP pressure to the Auxiliary
reservoir. when the handle is parallel to the body, it is
an open position for the cock the main difference
between the angle cock and IC is that IC is used to
isolate the pressure of certain component while AC is
used to isolate the pressure of the whole coach.

11.  Brake Cylinder:On every coach fitted with air brake system two brake
cylinders are provided for actuating the brake rigging for the application
and release of brakes. During application of brakes the brake cylinder
develops mechanical brake power by outward movement of its piston
assembly after receiving air pressure from Auxiliary reservoir through
the distributor valve, This is transmitted to the brake shoes through a
combination of levers. During release action of brakes the compression
spring provided in the brake cylinder brings back the rigging to its
original position.

12.  Bogie mounted air brake system
 Coaches are fitted with twin pipe system which are connected to compressor located in the locomotive and the pipe 1)FP 2)BP
are running throughout the train. At the end of the coach the pipes are sealed with dummy plug. The compressed air generated by
compressor is stored in main reservoir(MP). FP pressure is 6 kg/cm^2 and BP pressure is 5 kg/cm^2. MR is of 10 kg and
auxiliary reservoir (AR) is of 200 litres. The air from MR moves into FP & BP. From FP it goes to dirt collector then isolating
cock (IC) and through check valve into AR. From BP it goes to dirt collector then to common pipe bracket. The air from AR also
moves into CPB. From CPB it moves into DV(distributor valve). AR pressure remain in the top chamber. Brake pipe pressure
enters the DV and goes into CR and becomes CR pressure (5 kg/cm^2). BP pressure and CR pressure are equalized as both are of
5 kg/cm^2 and the pressure are separated by diaphragm (rubber lining) which is connected to hollow stem.

13.  When the brake is released the AR pressure moves out of it to
the atmosphere. When the brake cylinder pressure reaches 3.8
kg/cm^2 maximum brake is applied. And when BP pressure
reaches 4.8 kg/cm^2 the brake cylinder pressure is released
through the IC which is vented to atmosphere.The dirt collector
uses centrifugal force to separate the dirt. Due to this force the
air moves and anticlockwise and heavy particles(dirt particles)
get collected at the bottom which is drain out using drain plug. It
also has a filter in it. When driver applies brakes means by
venting BP pressure to atmosphere from driver’s brake valve. The
reduction of the brake pipe positions the DV in such a way that
the AR is connected to brake cylinder through automatic pressure
modification(APM) based on position of sensor arm of APM
device it gives an output of + 0.1 kg per centimeter square for
loaded position of wagon and 2.2 kg/cm^2 for empty position
bracking. The brakes are released by increasing BP and by
exhausting the BC pressure through DV. PEAVD is emergency
breaking which reduces BP to 0 and brakes are applied, an alarm
on each coach is fitted to recognize the chain pull in coach.

14.  A. Charging stage :During this stage, brake pipe is charged to 5 kg/cm2pressure
and feed pipe is charged to 6 kg/cm2 pressure which in turn charges auxiliary
reservoir to 6 kg/cm2 pressure. At this stage, brake cylinder gets vented to
atmosphere through passage in Distributor valve.
 B. Application Stage :For application of brakes, the pressure in brake pipe has to
be dropped. This is done by venting air from driver’s brake valve. Reduction in
brake pipe pressure positions the distributor valve in such a way that the control
reservoir gets disconnected from brake pipe and auxiliary reservoir gets
connected to brake cylinder. This results in increase in air pressure in brake
cylinder resulting in application of brakes. The magnitude of braking force is
proportional to reduction in brake pipe pressure
 C. Release stage :For releasing brakes, the brake pipe is again charged to 5
kg/cm2 pressure by compressor through driver’s brake valve. This action
positions distributor valve in such a way that auxiliary reservoir gets isolated
from brake cylinder and brake cylinder is vented to atmosphere through
distributor valve and thus brakes are released.

15.  LIMITATIONS :
 If the brakes are applied before recharging has been completed, a larger brake
pipe reduction will be required in order to achieve the desired amount of
braking effort.
 If the brake pipe pressure is too low due to an excessive no. of brake
applications, an emergency application will not produce a large enough
volume of air flow to trip the triple valves, leaving the engineer with no
means to stop the train.
 Two pipe system is better than single pipe air brake system because this
additional enhancement adds the main reservoir pipe, which is continuously
charged with air directly from the locomotive's main reservoir. This
arrangement help to reduce the pressure loss problems and also reduces the
time required for the brakes to release, since the brake pipe only has to
recharge itself.

16.  CONCLUSIONS:Vacuum brakes have extremely limited applications
because of longer longer to function and unsuitable for high speed trains.
 Air brakes are efficient as compared to vacuum brakes; however they require
considerable stopping distance therefore cannot be used for emergency
braking.
 Reference: www.reseachgate.com
www.wikipedia.com
www.seminarsonly.com
www.indianrailway.gov.in
www.jrtr.net

17. THANK YOU