Brake Continuity Test
by Prakash Tendulkar, 2005
Disclaimer: The information presented here is neither complete nor accurate. Complete details on the topics here are available only from Indian Railways and other official organizations. The material here is not a substitute for the official documentation or official training procedures, which are provided to duly authorized personnel. Do not use the information here to design, build, operate, repair, or maintain any equipment.
The material below is based on information gathered from working timetables and other sources.
A Brake Continuity test on air brakes MUST invariably be conducted in the manner detailed below, in the following circumstances:
- At the Originating station
- When a fresh locomotive or additional locomotive is attached
- Whenever any vehicle is attached or detached
- When brake pipe is disconnected to rectify any defect
The test is conducted by the guard upon receiving acknowledgement that the brake pipe is charged. The guard applies brakes in a documented method and the driver acknowledges this when a specific drop in pressure is observed in the gauges located in the locomotive.
In the absence of a guard, an employee from the Carriage & Wagon department performs the test.
At major stations and at crew change points, Carriage & Wagon department employees perform a similar test and hand over the Brake Certificate to the driver by observing the pressure drop from an SLR coach or pantry car nearest to locomotive.
For passenger trains, the guard signs the Brake Certificate and sends it to the driver through the C&W employee. The driver will NOT start the rake unless he receives this certificate. The guard and driver also communicate over the walkie-talkie the pressure readings that are observed.
In vacuum braked trains, drivers could override ACP (Alarm Chain Pulling) by placing the brake controller in the 'release' position. This would force exhausters to operate at full capacity to generate sufficient vacuum to keep the train rolling.
However, this method does not work upon train parting as the flow of air through a disconnected hose is more than what exhausters can override, but again, the length of freight train makes a difference at times for vacuum brakes.
For air-braked rakes, there is no override possible and the rake comes to a standstill after brakes are engaged through the application of the emergency alarm chain.
Of course, there is always the human factor involved, and safety measures can always be defeated. Erroneous certificate issued by the C&W employee or the guard, a miscreant tampering with the angle cock (also called isolation cock), or disconnected couplers are but a few of the problems that can still affect the train's brake power.
It is exactly for this reason that the driver and guard exchange signals with the station masters and cabin men while passing them. The station masters and cabin men verify that the last carriage has its LV sign on it (during the day) or that the red lamp is lit (at night). Otherwise, station master and cabin men of the next station are notified.