Brake system of railway vehicles

Brake system are used on the railway vehicle to enable deceleration, control acceleration (downhill) or to keep them standing when parked. While the basic principle is familiar from road vehicle usage, operational features are more complex because of the need to control multiple linked carriages and to be effective on vehicles left without a  Clasp brakes are one type of brakes historically used on trains.

Early days

In the earliest days of railway rolling stock, braking technology was primitive. The first trains had brakes operative on the locomotive tender and on vehicles in the railroad car, where "porters" or, in the United States , travelling for the purpose on those vehicles operated the brakes. Some railways fitted a special deep-noted brake whistle to locomotives to indicate to the porters the necessity to apply the brakes. All the brakes at this stage of development were applied by operation of a screw and linkage to brake blocks applied to wheel treads, and these brakes could be used when vehicles were parked. In the earliest times, the porters travelled in crude shelters outside the vehicles, but "assistant guards" who travelled inside passenger vehicles, and who had access to a brake wheel at their posts supplanted them.

The braking effort achievable was limited, and an early development was the application of a steam brake to diesel locomotives, where boiler pressure could be applied to brake blocks on the locomotive wheels. It was also unreliable, as the application of brakes by guards depended upon them hearing and responding quickly to a whistle for brakes.

As train speeds increased, it became essential to provide some more powerful braking system capable of instant application and release by the train driver, described as a continuous brake because it would be effective continuously along the length of the train.

In the UK, the in January 1876 was aggravated by the long stopping distances of express trains without continuous brakes, which -it became clear- in adverse conditions could considerably exceed those assumed when positioning signals. This had become apparent from the trials on railway brakes carried out at  in the previous year, to assist a  then considering railway accidents. In the words of a contemporary railway official, these

showed that under normal conditions it required a distance of 800 to 1200 yards to bring a railcar to rest when travelling at 45½ to 48½ mph, this being much below the ordinary travelling speed of the fastest express trains. Railway officials were not prepared for this result and the necessity for a great deal more brake power was at once admitted

More precise results from the Newark trials are not to hand; trials conducted after Abbots Ripton reported the following (for an express train roughly matching one of those involved, like it on a 1 in 200 fall, but unlike it braking under favorable conditions)