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Brake van and guard's van are terms used mainly in the UK, Australia and India for a railway vehicle equipped with a hand brake which can be applied by the guard. The equivalent North American term is caboose, but a British brake van and a caboose are very different in appearance, because the former usually has only four wheels, while the latter usually has bogies. Many British freight trains formerly had no continuous brake so the only available brakes were those on the locomotive and the brake van. Because of this shortage of brake power, the speed was restricted to . The brake van was marshalled at the rear of the train so both portions of the train could be brought to a stand in the event of a coupling breaking. When freight trains were fitted with continuous braking, brake vans lost their importance, and were discontinued by many railways. However, they still continue on some important railways, such as the Indian Railways, besides the heritage railways. ==Origin== Railways were a formalised development of industrial tramways, which had found need on occasions to add additional braking capacity by adding an empty truck to the rear of a group of tramcars. This allowed the "locomotive" — often a cableway powered by a steam engine at the surface — to operate both safely and, more importantly, at higher speed. The first railways, such as the pioneering Liverpool and Manchester Railway of 1830, used a version of the tramways buffer and chain coupling, termed a screw-coupling. Vehicles are coupled by hand using a hook and links with a turnbuckle-like device that draws the vehicles together. Vehicles have buffers, one at each corner on the ends, which are pulled together and compressed by the coupling device. With no continuous brake across the entire train,〔 the whole train was reliant on the braking capacity of the locomotive, and train lengths were restricted. To allow for longer trains, early railway companies from the 1840s onwards began replicating industrial tramway practises, by adding "break vans". The term was derived from their name on the industrial tramways, in which they controlled the (residual) train if there was a "break" in the linkage to the locomotive. Early railway couplings had been found to be prone to breakages. The term was only replaced by "brake van" from the 1870s onwards. Because of the combined risks of shortage of brake power and breaking couplings, the speed of freight trains was initially restricted to . The brake van was marshalled at the rear of the train, and served two purposes: *Provided additional braking for 'unfitted' goods trains *Put a man (the guard) at the rear of the train, who could take action in the event of a breakdown or accident While the UK railway system persisted until post-nationalisation in 1948 with "unfitted" (discontinuously braked) trains and loose couplings (the final unfitted trains ran in the 1990s), other systems, such as the North American adoption of the Janney coupler, overcame the same railway safety issues in a different manner. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「brake van」の詳細全文を読む スポンサード リンク
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