VACUUM BRAKING SYSTEM — Carengineered.com

Introduction

In history when Britishers began expanding their empire needed for increase in the trade and commerce as it directly meant, with an increase in the trade and commerce of any estate be it provincial or under direct control of the Britishers, more amount of money was to be generated that means more salaries were to be paid off, thus leading to expansion of an overall empire.

The Locomotives then initially used manual braking system with a crew in all the respected attached boogies and were given signals by the driver to collectively apply the brakes for the effectiveness, that usually were missed by the crew for N number of reasons.

later Vacuum Braking system were employed, in which all the boogies were connected with a series of pipes and the braking in all the boogies could be controlled by the single driver’s effort by simply adjusting the vacuum regulation depending upon the type of braking, manually, that would in turn compress the piston to push the brakes in direction opposing the wheel’s rotation.

But there was a defect in such a mechanical braking system, that any minute displacement of the pipes, or even the leakage were heavily responsible for the malfunctioning of the the entire braking system, thus nullifying the efforts.

Components of Automatic Vacuum Braking System

Driver’s Brake Valve

Driver’s Brake Valve means the valve controlled by the driver, that functions to the extent to which the valve is to be opened in order to release the compressed air out from the respected pipes or the reservoir.

Exhauster

This mechanical component has 2 speeds, ie High and Low speeds.

The High speed is that increases the speed for the creation of the vacuum, thus to release the brakes while the low speed is triggered in order to maintain a vacuum amount to maintain the brake release.

Brake Pipe

It is the pipe responsible for the transfer of the vacuum throughout the entire length of the train.

Dummy Coupling

At the end of each vehicle a dummy coupling is provided to make sure the end of the brake pipe hoses to be sealed when the vehicle is uncoupled.

Coupled Hoses

The brake pipes between the 2 adjacent boogies are to be carried out through these flexible hoses.

Brake Cylinder

The piston is contained inside the brake cylinder which operates the brakes through the links called ‘RIGGING’.

Vacuum Reservoir

The effective working of the vacuum braking system is dependent upon the difference between pressure of both the sides of the brake cylinder.

In order to confirm effective braking and the availability of the vacuum, a reservoir is connected to the upper side of the piston.

Brake Block

It is therefore the main component of the braking system and is similar to the conventional brake pads.

This Block is usually made up of the caste iron material that rubbs against the walls of the wheel, hence opposing its motion.

While restricting the motion a large amount of heat is liberated and hence wears the block over time.

Brake Rigging

It is basically a link mechanism that allows the piston inside the brake cylinder to transmit the pressure directly to the brake block.

Quite sophisticated adjustments are needed for an effective braking effort.

Ball Valve

This valve is generally employed in order to maintain the desired vacuum inside the vacuum reservoir.

Working

Under normal running conditions a partial vacuum is maintained inside the train pipe, and the brakes are thus released.

When the air is introduced inside the train pipe, the air that is at the atmospheric pressure acts against the pistons present inside the cylinders in each of the vehicle.

A vacuum is acting on the other face of both the pistons, so that a net force is applied. A mechanical linkage (Rigging) transmits this force to the brake shoes which act against the wheels.

The brake cylinder is mounted inside a larger housing, this provides a reserve of vacuum as the piston operates.

The cylinders are mounted slightly in order to maintain the alignment with the brake rigging cranks, so that it is supported in by the trunnion bearings, and also the vacuum pipe connected to it is flexible.

The piston mounted inside the brake cylinder has a flexible piston ring to allow the air to pass through the upper part of the cylinder into the lower part of the cylinder.

During the vehicle at rest, the brake is not charged, so the brake pistons would have automatically dropped to their lower position in the absence of a pressure difference.

If the driver now moves his control to the “brake” position, air is introduced into the train pipe. According to the driver’s manipulation of the brake control, some or all of the vacuum must be destroyed during the process.

The ball valve closes and there is a higher air pressure under the brake pistons as compared to above it, and the pressure difference thus forces the piston to rise upwards, applying the brakes. The driver can thus control the amount of braking force by supplying more or less air into the train pipe.

Originally published at https://www.carengineered.com on September 14, 2020.