Air Brake System Fundamentals

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Questions and Answers

What is the primary function of the charging stage in the air brake system?

It charges the air brake system to regime pressure. (correct)

It limits maximum brake cylinder pressure.

It controls the time for brake application.

It facilitates the release of brake pressure.

What role does the main valve play during brake operation?

It facilitates graduated brake application.

It connects the brake cylinder to atmosphere. (correct)

It reduces pressure in the brake pipe.

It increases pressure in the brake pipe.

How does the system quickly propagate a reduction of pressure in the brake pipe?

By activating the quick service valve.

By charging the air brake system.

By manually adjusting the brake pipe pressure.

By locally reducing air pressure in the distributor valve. (correct)

What is the purpose of the graduated brake release?

To assist in increasing brake pipe pressure in steps. Signup and view all the answers

What aspect does the system control to determine brake application and release timing?

Service conditions. Signup and view all the answers

What is the pressure the feed pipe is charged with throughout the length of the train?

6 Kg/cm2 Signup and view all the answers

Which component is responsible for charging the brake system with compressed air?

The locomotive compressor Signup and view all the answers

What happens to the control reservoir during the brake application stage?

It disconnects from the brake pipe Signup and view all the answers

Which of the following correctly describes how brake application occurs?

By venting air from the driver's brake valve Signup and view all the answers

What is the charging pressure of the brake pipe throughout the train?

5 Kg/cm2 Signup and view all the answers

What is the primary function of the auxiliary reservoir in the air brake system?

To store compressed air Signup and view all the answers

Which of the following pressures is associated with brake application?

Dropping pressure in the brake pipe Signup and view all the answers

What feature of the IRSA-450 slack adjuster ensures that no manual adjustments are needed after initial setting?

Fully Automatic Signup and view all the answers

What is the primary purpose of the jacking tool mentioned in the context of overhauling the slack adjuster?

For mass repair and overhauling Signup and view all the answers

Which part of the slack adjuster is essential for controlling the adjustment of the brake shoe clearance?

Leader nut unit Signup and view all the answers

What happens to the brake shoe clearance when the IRSA-450 slack adjuster becomes Double-Acting?

It is adjusted both ways, automatically Signup and view all the answers

Which tool is specifically mentioned for external use in the overhauling of slack adjusters?

Straight nose pliers Signup and view all the answers

Which of the following statements about the IRSA-450 slack adjuster is incorrect?

It requires frequent manual adjustments. Signup and view all the answers

What can cause resistance during brake application in the context of the slack adjuster?

Heavy brake rigging Signup and view all the answers

Which tool is used to create secure connections or adjustments while overhauling the slack adjuster?

Pipe vice Signup and view all the answers

Which of the following is NOT listed as a tool for overhauling the slack adjuster?

Hammer Signup and view all the answers

What is the weight capacity of the barrel spring?

140 kg Signup and view all the answers

Which of the following is NOT a required replacement part during the POH of the slack adjuster?

Rubber gasket part No.(5) Signup and view all the answers

How many times should the pay-in and pay-out tests be repeated?

A couple of times Signup and view all the answers

What must be done with the slack adjuster if it has badly rusted parts?

Replace it Signup and view all the answers

Which spring has the smallest diameter mentioned in the specifications?

Take out spring Signup and view all the answers

For the pay-out test procedure, what is done after turning up the control rod?

Make two brake applications Signup and view all the answers

Which part is attached to the free end of the spindle during the take up test?

Slack adjuster Signup and view all the answers

What is the diameter of the clutch spring?

38 mm Signup and view all the answers

What operation should be performed after allowing the slack adjuster to take up?

Measure the stroke Signup and view all the answers

Which weight corresponds to the pay out spring?

58 Kg Signup and view all the answers

What is referred to as the heart of the air brake system?

Distributor valve Signup and view all the answers

Which component of the C3W distributor valve senses changes in brake pipe pressure?

Distributor valve Signup and view all the answers

What occurs to the brake pipe pressure when brakes are applied?

It drops Signup and view all the answers

Which component is NOT part of the C3W distributor valve?

Control valve Signup and view all the answers

For effective functioning of the air brake system, which stage must the distributor valve operate during?

Charging stage Signup and view all the answers

What is the role of the driver's brake valve in relation to the distributor valve?

To control brake pipe pressure changes Signup and view all the answers

Which of the following is a function of the distributor valve?

Increasing the brake pipe pressure for release Signup and view all the answers

Which component is responsible for quick brake application in the C3W distributor valve?

Quick Service valve Signup and view all the answers

What happens to the pressure during brake release?

It decreases Signup and view all the answers

Which device ensures that the air system does not receive too much pressure?

Limiting device Signup and view all the answers

What is indicated by the pressure gauge at point 6b when the isolating cock is opened?

10 Kg/cm2 Signup and view all the answers

What should be done if a leakage is detected at the hose nipple or coupling?

Attend to or replace the clamp Signup and view all the answers

During the testing procedure, how should the hose coupling assembly be prepared?

Immerse in a tub of water Signup and view all the answers

In the context of the test bench, what is the specified pressure for the flexible hose?

10 Kg/cm2 Signup and view all the answers

What component is used to control the air flow to the hose assembly during the test?

Isolating cock Signup and view all the answers

Which part is essential for establishing a leak-proof connection in the hose assembly?

Clamp Signup and view all the answers

What is the proper method for checking the integrity of the hose coupling assembly?

Submerge in water and check for bubbles Signup and view all the answers

What occurs when the brake cylinder pressure reaches 3.8 kg/cm2 during an emergency application?

The check valve at the top closes, stopping the entry of compressed air. Signup and view all the answers

During the application stage, what is the role of the differential pressure across the diaphragms?

It facilitates the movement of the hollow stem upward to enable pressure entry. Signup and view all the answers

What happens to the valve positions after the brake pipe pressure is rapidly reduced to 0 kg/cm2?

The various valves will reposition based on the new differentials created. Signup and view all the answers

What is the function of the check valve in relation to the main valve during the brake cylinder charging process?

To close and maintain the lap position after charging is completed. Signup and view all the answers

How does the emergency application impact the flow of air into the brake cylinder?

It prevents the flow of compressed air after the target pressure is reached. Signup and view all the answers

What should be done to the slack adjuster spindle before reassembly?

Coat it with semi-fluid grease Signup and view all the answers

Which part needs to be inspected for burrs during slack adjuster assembly?

Safety collar Signup and view all the answers

What is the final step in testing the slack adjuster after installation?

Conduct two brake applications to check piston stroke Signup and view all the answers

What must be confirmed about the spring dowel sleeve pin after securing the safety collar?

Its ends must not protrude above the collar surface Signup and view all the answers

After testing, what action should be taken with the slack adjuster on the test rack?

Unscrew the adjuster ear Signup and view all the answers

What type of grease is specified for lubricating the slack adjuster parts?

Semi-fluid grease SERVOGEM -RR3 or MALMEROL MULTIGREASE LL3 Signup and view all the answers

What should be done if there are burrs on the collar during assembly?

Smooth them off with a file Signup and view all the answers

What object is suggested to be used temporarily during the brake application tests?

An iron object such as a hammer Signup and view all the answers

What is the purpose of the spring dowel sleeve in the slack adjuster assembly?

To secure the safety collar tightly Signup and view all the answers

What occurs when the handle of the cut off angle cock is positioned parallel to the body?

It opens the inlet port for air passage. Signup and view all the answers

Which component within the cut off angle cock prevents air from escaping?

Nitrile rubber seat Signup and view all the answers

What is the first step in the dismantling procedure of the cut off angle cock?

Hold the cut-off angle cock in a vice. Signup and view all the answers

What feature of the steel ball in the cut off angle cock aids in venting air?

The groove at the bottom Signup and view all the answers

Which tool is primarily used to detach the cap from the body of the cut off angle cock?

Screwdriver Signup and view all the answers

What action is required if the spring within the cut off angle cock is found to be heavily rusted?

Replace it only if necessary. Signup and view all the answers

What connects the inlet port to the outlet port in the cut off angle cock when in open position?

The steel ball with a hole Signup and view all the answers

Which action is necessary after unscrewing the four hexagonal bolts of the cut off angle cock?

Detach the cap from the body. Signup and view all the answers

Which position is indicated when the handle of the cut off angle cock is perpendicular to the body?

Closed position cutting off air. Signup and view all the answers

What should be done to the guard's emergency brake valve before the brake pipe pressure is recharged?

Reset the emergency brake valve to normal position manually. Signup and view all the answers

Which material should rubber or leather components be stored away from?

Heat, alcohol, and acids Signup and view all the answers

During the procedure to overhaul the guard's emergency brake valve, which tool is used to apply light pressure?

Light hammer Signup and view all the answers

What is the first step to be taken once the guard's emergency brake valve is dismantled?

Drain out any remaining fluids. Signup and view all the answers

What should be checked against when assembling the guard's emergency brake valve?

RDSO drawing no SK-73549 Signup and view all the answers

What is required to fit the 'O' rings on the spindle during assembly?

Light grease to aid installation Signup and view all the answers

In addition to the special spanner, which tool is necessary for removing the gland during overhauling?

Spanner for removing thread plug Signup and view all the answers

How often should the guard's emergency brake valve be overhauled?

Every POH (Periodical Overhaul) Signup and view all the answers

Which component should sit properly in the bore of the body during assembly?

Seat ring Signup and view all the answers

What must be ensured about the 'O' rings before inserting the spindle into the bore?

They must be undamaged. Signup and view all the answers

Study Notes

Air Brake System

The air brake system utilizes compressed air to operate brakes.
Locomotives use compressors to charge the feed pipe and brake pipes throughout the train.
The feed pipe connects to the auxiliary reservoir, and the brake pipe connects to the brake cylinder via the distributor valve.
Brake application involves reducing pressure in the brake pipe.

Classification of Air Brake System

Figure 4.1 illustrates a twin pipe graduated release air brake system on main line coaches.
Components and their placement are shown.

Principle of Operation

The operating principle of the twin pipe graduated release air brake system is detailed visually in Figure 4.1.

Charging the brake system

Brake pipes are charged to 5 kg/cm².
Feed pipes are charged to 6 kg/cm².
The control reservoir is pressurized to 5 kg/cm².
The auxiliary reservoir is pressurized to 6 kg/cm².

Brake Application Stage

To apply brakes, release air from the brake pipe.
Disconnecting the control reservoir from the brake pipe is part of the brake application procedure and action of other mechanisms.
Subsequently, the control reservoir is disconnected from the brake pipe.

Air Brake Sub-Assemblies

Components of the air brake system include common pipe bracket, intermediate piece/sandwich piece, air hoses , brake cylinder, cut-off angle cocks, dirt collector, auxiliary reservoir, and guard's emergency brake valve.

Common Pipe Bracket

This bracket is attached to the underside of the coach frames.
It supports distributor valves.
All types of distributor valves use this bracket.

Intermediate Piece

A fitting for adapting the type of distributor valve.
Ensures suitable connections to the common pipe bracket.

Air Brake Hose

Brake pipe and feed air pipe hoses connect train sections for air pressure continuity.
Hose paint codes are used for identification: green for brake pipe and white for feed pipe.
Inspections for air leaks are part of the test procedure.

Cut-Off Angle Cock

These cocks are on both brake pipe and feed pipe ends of each vehicle.
These cocks enable air hose coupling/disconnecting.

Test Procedure

Hose couplings are tested on a bench.
Test procedure involves checking for leaks and pressurization with a dummy head (figure 4.3) and immersion in water.
Check valves to determine serviceability through leakage test procedures.
Other procedures involve isolating cocks and pressurizing to 10 kg/cm² to verify leakage.

Brake Cylinders

Every coach has two brake cylinders for actuating the brake rigging/mechanisms.
They are used for brake application and release.
Cylinder bodies are constructed from sheet metal or cast iron.
There is a dome cover that protects the spring mechanism.

Dismantling Brake Cylinders

Specific steps for disassembling brake cylinders under maintenance require tools and techniques (figure 4.5).

Cleaning and Replacing Brake Cylinder Components

A procedure is followed for cleaning and replacing damaged parts (figure 4.5).
It involves specific tools and procedures for replacing and cleaning components in the brake cylinder.

Dirt Collector

The dust collector is mounted inside the brake pipe line and feed pipe line.
The system prevents dust from getting to the air brake components for optimal performance.

Auxiliary Reservoir

This is a cylindrical sheet metal tank.
Flanges support pipe connections at each end of the auxiliary reservoir tank.
A drain cock is included for draining condensation/moisture.
It is inspected/maintained during every periodic maintenance.

Guard's Emergency Brake Valve

The guard's emergency brake valve allows for emergency brake application.
The valve is designed for use by guards in crisis situations.
Its design ensures a predictable effect on the brake system.

Slack Adjuster

This device adjusts the space between the wheels and the brake blocks.
It ensures consistent brake application/disengagement during use.
This includes manual and automatic adjustment.

Distributor Valve

The distributor valve (often called the 'heart' of the air brake system) senses pressure changes in the brake pipe and triggers appropriate brake activation/deactivation.
It manages graduated, emergency, and normal applications.
Multiple types exist, including C3W, KE, and P4aG.

Testing of Auxiliary Reservoir

A pressure test is performed.
Hydraulic test is conducted to verify the reservoir has no leaks.
Standard procedures are followed for evaluating the air and hydraulic pressures

Safety Precautions

Specific tools are required during assembly and disassembly tasks.
Appropriate care of the rubber/leather components is necessary.

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Description

Test your knowledge on the air brake system's mechanics with this quiz. Explore the functions of various components like the charging stage, main valve, and pressure propagation. Understand the nuances of brake application and release timing.