|
Brakes are used on railway trains to bring the train to a standstill. For the type of ferns known as brakes, see brake (fern). ...
A typical North American steam train In rail transport, a train consists of rail vehicles that move along guides to transport freight or passengers from one place to another. ...
In the earliest days of railways, braking was primitive and relied on a mixture of:
- brakes on the locomotive.
- putting the locomotive into reverse.
- calling for additional application of handbrakes by whistle signals.
- hauling special brake vans to assist with the braking effort.
- pushing special brake tenders ahead of a diesel locomotive to increase braking effort.
- engineering the lines with gentle gradients so that weak brakes were reasonably effective.
- catchpoints and safety sidings to prevent runaways doing too much damage.
- sidings to enable heavy trains to be divided into convenient portions.
- applying and releasing handbrakes at the top and bottom of steep descents.
As train loads increased, gradients steepened, and speeds increased, braking became a problem. In the late 19th century, significantly better continuous brakes started to appear, either air operated or vacuum operated. These brakes used hoses connecting all the wagons of a train, so the driver could apply or release the brakes with a single valve in the locomotive. A locomotive (from Latin loco motivus) is a railway vehicle that provides the motive power for a train, and has no payload capacity of its own; its sole purpose is to move the train along the tracks. ...
Two cupola cabooses, a transfer caboose and a bay window caboose in Ohio. ...
Horizontal line (use sparingly)d grade for the grade or gradient of roads and other geographic features. ...
Catchpoints are a set of railway points used to deflect any runaway wagons away from a mainline, if needs be derailing them in the process. ...
A sand drag or sand trap is a device used to stop runaway railway wagons. ...
A siding, in general rail terminology, refers to a section of rail used to store stationary rolling stock perhaps whilst it is loaded or unloaded, or alternatively, a short length of rail that provides access to and from factories, mines, quarries, wharves, etc. ...
Piping diagram from 1920 of a Westinghouse E-T Air Brake system. ...
The vacuum brake is a braking system used on trains. ...
These continuous brakes can be simple or automatic, the key difference being what happens should the train break in two. With simple brakes, pressure is needed to apply the brakes, and all braking power is lost if the continuous hose is broken for any reason. Simple non-automatic brakes are thus useless when things really go wrong, as is shown with the Armagh rail disaster. The Armagh rail disaster happened on June 12, 1889 near Armagh, Northern Ireland. ...
Automatic brakes on the other hand use the air or vacuum pressure to hold the brakes off against a reservoir carried on each vehicle, which applies the brakes if pressure/vacuum is lost in the train pipe. Automatic brakes are thus to a great extent "fail safe". The term fail-safe is used to describe: A device which, if (or when) it fails, fails in a way that will cause no harm or at least a minimum of harm to other devices or danger to personnel. ...
The standard Westinghouse Air Brake has the additional enhancement of a triple valve, and local reservoirs on each wagon that enable the brakes to be applied fully with only a slight reduction in air pressure, reducing the time that it takes to release the brakes as not all pressure is voided to the atmosphere. The air brake was invented by George Westinghouse of New York State in 1868. ...
Non-automatic brakes still have a role on engines and first few wagons, as they can be used to control the whole train without having to apply the automatic brakes.
Air versus vacuum brakes
In the early part of the 20th century, many British railways employed vacuum brakes rather than the air brakes used in America and much of the rest of the world. The main advantage of vacuum was that the vacuum can be created by a steam ejector with no moving parts (and which could be powered by the steam of a steam locomotive), whereas an air brake system requires a noisy and complicated compressor. The vacuum brake is a braking system used on trains. ...
Piping diagram from 1920 of a Westinghouse E-T Air Brake system. ...
A steam ejector is a device which uses high pressure steam to create a vacuum. ...
Scheme of steam locomotive. ...
A gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume. ...
However, air brakes are much more efficient than vacuum brakes, capable of generating a pressure of 90psi vs only 15psi for vacuum. With a vacuum system, the maximum pressure differential is atmospheric pressure (14.7psi at sealevel, less at altitude). This advantage of air brakes increases at high altitude, e.g. Peru. This much higher efficiency, and the demise of the steam locomotive, has seen the air brake become ubiquitous; vacuum braking is no longer in large scale use anywhere in the world.
Air brake enhancements One modern enhancement of the automatic air brake is to have a second air hose (the main reservoir or main line) along the train to recharge the air reservoirs on each wagons. This air pressure can also be used to operate loading and unloading doors on wheat, coal and ballast wagons. On passenger coaches, the main reservoir pipe is also used to supply air to operate the external doors, and where fitted powered internal doors and air suspension. A railroad car (or, more briefly, car, not to be confused with railcar), also known as an item of rolling stock, is a vehicle on a railroad (or railway) that is not a locomotive — one that provides another purpose than purely haulage, although some types of car are powered. ...
Accidents with brakes The Armagh rail disaster happened on June 12, 1889 near Armagh, Northern Ireland. ...
Wikipedia does not yet have an article with this exact name. ...
John Axon GC (4 December 1900–9 February 1957) was an English railway driver, from Stockport, who died while driving a runaway steam locomotive whose steam brakes had failed. ...
The Gare de Lyon train accident happened on June 27, 1988 when a commuter train inbound to the Gare de Lyon station in Paris crashed into a stationary train killing 56 people. ...
References The British Transport Commission (BTC) was created by Clement Attlees post-war Labour government as a part of its nationalisation programme, to oversee railways, canals and road freight transport in Great Britain (Northern Ireland had the separate Ulster Transport Authority). ...
See also |
Feeds |
Contact