ABS in IR

1. NALLA MALLA REDDY ENGINEERING COLLEGE
DEPARTMENT OF MECHANICAL ENGINEERING
Mini project presentation
on
Air Brake System Used In Diesel Locomotives
Under the guidance of
DR.ASIT KUMAR PARIDA
ASSOCIATE PROFESSOR
By
KONDI NAVEEN
20B65A0311

2. ABSTRACT
 The mini project carried out by me was the “Air Brake System used in Diesel Locomotives” in Diesel loco shed
Moula-Ali.
 The purpose of braking action is to perform controlled reduction in velocity of the train, either to reach a certain
lower speed or to stop at a fixed point. In general, the braking is done by applying frictional resistance to the
moving wheels in order to slow down or stop the train.
 In this presentation, the types of air brake systems used in diesel locomotive is discussed along with the
important components of air brake system.

3. LOCOMOTIVE AIR BRAKE SYSTEM
 A locomotive air brake system is a power braking system with compressed air as the operating medium. Thus, it is
also known as pneumatic braking system. Modern trains rely upon a fail-safe air brake system that is based upon a
design patented by George Westinghouse on April 13, 1869.
Figure 1: Schematic diagram of Loco Air Brake System

4. CLASSIFICATION OF LOCOMOTIVE AIR BRAKE SYSTEM
On the basis of type of release, air brake system is classified as:
a)Direct release air brake system: Direct release brakes mean that if the pressure in the brake pipe rises by only a
couple of pounds, the brakes will completely release on all cars in the train.
b)Graduated release air brake system: Graduated release means that as the brake pipe pressure rises, the brakes will
release in proportion to the pressure rise.
Both direct and graduated release are further available in two forms:
a)Single pipe air brake system: Single pipe air brake system consists of a single pipe called brake pipe runs over the
train through which the compressed air is fed for the application of brakes.
b)Twin pipe air brake system: Twin pipe air brake system consists of two pipes that is brake pipe and feed pipe run
over the train. Brake pipe helps in application of brake and feed pipe is used to fill auxiliary reservoir faster for quick
release of brakes.

5. WORKING PRINCIPLE OF SINGLE PIPE AIR BRAKE SYSTEM
The Single Pipe Air Brake System in locomotive uses only single pipe called brake pipe to supply the air which is
compressed in the compressor for application of brakes. The working principle of single pipe air brake system consists of
three stages. They are:
a) Charging stage:
Figure 2: Charging stage
• During this stage, brake pipe is charged to 5kg/cm² pressure with
compressor by operating driver’s valve.
• The control reservoir and auxiliary reservoir are also charged to
5kg/cm² pressure via distributor valve.
• At this stage, brake cylinder gets vented to atmosphere through
passage in distributor valve.

6. b) Application Stage:
Figure 3: 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.

7. c) Releasing stage:
Figure 4: Releasing stage
• For releasing brakes, the brake pipe is again charged to
5kg/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.

8. WORKING PRINCIPLE OF TWIN PIPE AIR BRAKE SYSTEM
 The working principal of Twin Pipe Air Brake System of Locomotive is almost similar to that of the Single Pipe Air
Brake System including the three stages Charging, Application and Releasing of the brakes.
 But the only difference in Twin Pipe Air Brake system is that it contains two pipes which runs parallel to each other
over the train.
 After application of the brakes the Auxiliary Reservoir needed to be refilled/recharged with the compressed air
through brake pipe to release the brakes.
 Due to the use of single pipe in the system there is a delay in recharging the Auxiliary Reservoir for releasing the
brakes, to overcome this problem the Twin Pipe Air Brake System is designed.

9. Figure 5: Twin pipe air brake system
• The blue colour pipe is brake pipe which is charged
with compressed air of pressure 5kg/cm² by the
driver’s brake valve.
• The brake pipe is used to fill the control reservoir,
auxiliary reservoir and to apply and release the brakes
of locomotive.
• The red colour pipe is known as main reservoir pipe
or feed pipe, this pipe is used to fill the auxiliary
reservoir with the pressure of 6 kg/cm².
• It is equipped with non-return valve. Feed pipe helps
in faster recharging/refilling of auxiliary reservoir to
avoid delay in releasing of brakes and to provide
efficient operation of the air brake system.

10. BYPASS TWIN PIPE SYSTEM
Figure 6: Failure of brake pipe Figure 7: Bypassed brake pipe
 In case due to any reason, brake pipe of a coach or any wagon gets damaged or goes defective, it can be bypassed in
twin pipe system and the detachment of the coach or wagon not be essential as in the case of single pipe system.
 But in this, case the train will be worked as single pipe system.

11. COMPONENTS OF LOCOMOTIVE AIR BRAKE SYSTEM
Fig 9: Main Reservoir Fig 10: Brake Rigging
Fig 8: Air Compressor RR 80 101
Fig 11: Brake cylinder Fig 12: Brake Block

12. LOCOMOTIVE AIR BRAKE SYSTEM VALVES
Fig 13: Driver’s Brake Valve Fig 14: Feed Valve Fig 15: Distributor Valve

13. ADVANTAGES OF AIR BRAKE SYSTEM IN LOCOMOTIVE
 The supply of air is unlimited, so the brake system can never run out of its operating fluid, as hydraulic brakes
can.
 The locomotive air brake is a fail-safe brake because the failure or damage of the system or brake pipe causes a
pressure drop of air, which in turn applies the brake.
 Air line couplings are easier to attach and detach than hydraulic lines.

14. MAINTENANCE OF LOCO AIR BRAKES AND COMPRESSOR
 Repair ofAir Brake parts:
• Failure: Improper functioning of valves and other connections, noticed air leakage from valves and other parts.
• Cause of failure: Due to deformation of rubber O-Rings in valves and other parts of system due to ageing.
• Repairaction: Valves are overhauled with new O-Rings and other parts are also overhauled.
 Repairof Compressor and its parts:
• Failure: Desired quantity of air is not achieved.
• Cause of failure: Choking of after cooler pipes, due to scale formationbecause of high moisture content in the air.
• Corrective action: After cooler pipes are cleaned with dilute HCl solution to remove the deposited scale from the
pipes.

15. CONCLUSION
• From the above information, we have found that the air brake system is undoubtedly one of the most enduring
features of railway technology. It has lasted from its initial introduction in 1869 to the present day.
• The air brake system is still preferred as the best braking system .

16. THANK YOU