Buffer stop

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Two views of a Hayes-built bumper at the Linden Railroad Museum, Linden, Indiana.

Energy-absorbing buffer stop in France.

This buffer stop is designed to move up to 7 m to slow down a 850 t passenger train from 15 km/h without damaging the train or injuring passengers

A buffer stop or bumper (US) is a device to prevent railway vehicles from going past the end of a section of track.

The design of the buffer stop is dependent in part upon the kind of couplings that the railway uses, since the coupling gear is the first part of the vehicle that the buffer stop touches. The term buffer stop is itself of British origin, railways in Great Britain principally using buffer-and-screw couplings between vehicles.

1 Energy-absorbing buffer stops
2 Alternatives
3 Warning lights
4 Accidents

[edit] Energy-absorbing buffer stops

The large mass of a train, even at low speed, transfers a large amount of energy in a collision with a buffer stop. Ordinary buffer stops cannot cope. What is needed is some way of dissipating this energy, as through hydraulics or friction. Following a buffer stop accident at Frankfurt-am-Main in 1902, the Rawie company developed a large range of energy-absorbing buffer stops. Similar hydraulic buffer stops were developed by Ransomes & Rapier in the UK.

[edit] Alternatives

Lower cost alternatives to a buffer stop include railroad ties fixed to the rails, or a pile of dirt.

[edit] Warning lights

Buffer stops often have a fixed red light associated with them.

[edit] Accidents

The aftermath of the Gare Montparnasse accident

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Buffers

October 22, 1895 – Gare Montparnasse, Paris, France: express train overruns buffer stop and falls into street below
1902 – Frankfurt am Main, Germany: Serious buffer stop collision inspires development of Rawie range of energy-absorbing buffer stops.
27 July 1903; Glasgow St Enoch, 16 killed 27 injured
1948 - diesel train through buffer stops at Los Angeles
1970s - BART train went through buffer stops due to fault in ATO.
28 February 1975 - Moorgate Underground rail crash, 43 killed, 74 injured - buffer stop collision made far worse by dead end tunnel beyond
November 8, 1986 – Hua Lamphong, Bangkok, Thailand: 5 killed, 7 injured - buffer stop collision made by an unmanned train at a speed of 50 km/h.
8 January 1991 - Cannon Street station rail crash, London; 2 killed, 200+ injured - commuter train hits buffer stops
11 July 1995 - Largs - electric train went through buffer stops.
26 October 2006 - Kuala Lumpur buffer stop accident - a Star LRT train went through the buffer stops and dangled over the street.