View source for Buffer stop

{{Short description|Device to stop trains at end of track}}
{{Other uses of|bumper|Bumper (disambiguation){{!}}Bumper}}
[[File:Buffer stop zurich.jpg|thumb|175px|This buffer stop at [[Zürich Hauptbahnhof]] in [[Switzerland]] is designed to move up to {{convert|7|m}} to slow down an {{convert|850|t|adj=on}} passenger train from {{convert|15|km/h|abbr=on}} without damaging the train or injuring passengers.]]

A '''buffer stop''', '''bumper''', '''bumping post''', '''bumper block''' or '''stopblock''' (US), is a device to prevent [[Railroad car|railway vehicles]] from going past the end of a physical section of [[Track (rail transport)|track]].

The design of the buffer stop is dependent, in part, on the kind of couplings that the railway uses, since the [[Railway coupling|coupling gear]] is the first part of the vehicle that the buffer stop touches. The term "buffer stop" is of Italian origin, since railways in [[Italy]] principally use [[Buffers and chain coupler|buffer-and-screw couplings]] between vehicles.

== Types ==
Several different types of buffer stop have been developed. They differ depending on the type of coupler used and on the intended application.

* Buffer stops with [[anticlimber]]s. These are particularly important for passenger railway applications, because the anticlimbers reduce the likelihood of [[Telescoping (railway)|telescoping]] of the [[Passenger car (rail)|railroad cars]] during a head-on impact.
* Buffer stops for a [[Janney coupler|knuckle coupler]] or an [[SA3 coupler]] (centrally positioned between the two rails)
* Buffer stops with traditional "[[Buffer (rail transport)|buffers]]" on either side
* Hydraulic buffer stops
* Friction buffer stops (bolted down to the rail)

If there is extra room behind the bumper block, there is usually a sand or ballast drag that is designed to further retard a runaway train. One such accident occurred in 1975 on the [[London Underground|London Underground system]], when a Northern City Line train [[Moorgate tube crash|powered past the bumper block at Moorgate station]].

=== Energy-absorbing  ===
Largely because of its mass, a train transfers an enormous amount of [[kinetic energy]] in a collision with a buffer stop. Rigid buffers can safely cope only with very low-speed impacts. (''i.e.'', nearly stationary). To improve stopping performance, a way of dissipating this energy is needed, through compression or friction. Following a buffer stop accident at [[Frankfurt-am-Main|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.{{citation needed|date = February 2015}}

==== Examples ====

* Raja Trains Depot in Tehran
** Stopping speed: {{convert|20|km/h|abbr=on}}
** Stopping distance: {{convert|20|m|0|abbr=on}}.<ref>{{cite journal|title=Infrastructure (Iran)|journal=Railway Gazette International|date=January 2009|volume=1/2009|page=16}}</ref>
{{clear}}

=== Wheel stop ===
Wheel stops or car stops are used to stop small numbers of light vehicles at the end of level storage [[Track (rail transport)|tracks]] or to chock individual [[railroad car]]s on shallow [[Grade (slope)|grades]].<ref>{{Cite web | url=https://www.aldonco.com/store/c/56-Car-Stops.aspx | title=Aldon railcar wheel stops | access-date=2018-08-19 | archive-date=2018-08-19 | archive-url=https://web.archive.org/web/20180819182355/https://www.aldonco.com/store/c/56-Car-Stops.aspx | url-status=dead }}</ref><ref>{{Cite web | url=http://www.railsco.com/~wheel_stops.htm | title=Rails Company – Wheel Stops|archive-url=https://web.archive.org/web/20200130183517/http://www.railsco.com/~wheel_stops.htm|archive-date=January 30, 2020}}</ref><ref>{{Cite web|url=https://kimessteel.com/track-components/wheel-stops|title=Wheel Stops – Track Components|website=kimessteel.com}}</ref><ref>{{Cite web | url=http://www.westernsafety.com/products/wch-railroadproducts/wchpg7.html | title=Western Cullen Hayes Wheel and Car Stops | access-date=2018-08-19 | archive-date=2018-08-26 | archive-url=https://web.archive.org/web/20180826091927/http://www.westernsafety.com/products/wch-railroadproducts/wchpg7.html | url-status=dead }}</ref><ref>{{Cite web|url=https://nolancompany.com/car-stops/|title=Car Stops – The Nolan Company|website=nolancompany.com|date=4 February 2016}}</ref>

== Gallery ==
<gallery mode="packed" heights="150">
File:Hayes bumper, Linden, Indiana.jpg|Two views of a Hayes-built bumper at the [[Linden Depot|Linden Railroad Museum]], [[Linden, Indiana]]. This design accommodates the [[Janney coupler|AAR coupler]].
File:Buffer stop in Saint-Rémy-lès-Chevreuse (France).jpg|[[Shock absorber|Energy-absorbing]] buffer stop in [[France]]
File:QC-STM GarageBeaugrand 20040706-132759 VoieEssai.jpg|A buffer stop or [[sand drag]] on the [[Montreal Metro]] [[Honoré-Beaugrand station]]
File:VaughanSubwayTailtrack.png|Bumper at the end of a newer tunnel in the [[Toronto subway]] system beyond a terminal station
File:Scarborough Buffer Stop.jpg|Simple timber stop at [[Scarborough railway station|Scarborough]]
</gallery>

== Examples of accidents ==
[[File:Train wreck at Montparnasse 1895.jpg|thumb|right|The aftermath of the [[Montparnasse derailment|Gare Montparnasse accident]]]]
* 22 October 1895 – [[Gare Montparnasse]], [[Paris]], [[France]] – An express train [[Montparnasse derailment|overran the buffer stop and fell into the 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, Scotland]] – A train arriving at the St Enoch terminal station failed to stop in time and [[Glasgow St Enoch rail crash|collided heavily with the buffer stop]], sustaining severe damage. Sixteen people were killed, 13 instantaneously and 3 at a later time due to injuries received. 64 people were injured, of which 17 required hospital treatment.
* 15 January 1953 – [[Washington, D.C.]] – A train [[1953 Pennsylvania Railroad train wreck|jumped the platform and plunged through the concourse]] due to a faulty air break
* 28 February 1975 – [[Moorgate Underground rail crash]] – 43 killed, 74 injured – buffer stop collision made far worse by small size "tube" train running into larger dead-end tunnel beyond. The tunnel could accommodate full-size surface stock thus permitting the smaller train to concertina inside the tunnel.
* 13 April 1978 – [[Budapest]], [[Hungary]] – commuter train overruns a buffer stop owing to brake failure and crashes into the station building. 16 killed, 25 injured.<ref>{{cite news|title=A Csepeli Hév fekete áprilisa – 33 éve történt a tragikus HÉV baleset|url=http://csepel.info/?p=13607|access-date=11 November 2012}}</ref>
* 8 January 1991 – [[Cannon Street station rail crash]], London – 2 killed, 200+ injured – commuter train hits buffer stops.
* 22 February 2012 – [[Buenos Aires]], [[Argentina]] – [[2012 Buenos Aires rail disaster|a commuter train collided with buffer stops]] at a train station in Buenos Aires during the morning rush hour. The accident killed 51 people and injured more than 700 in Argentina's worst rail accident in 30 years.<ref>{{cite news|title=Argentine train crash kills 49 people, hurts 600|url=https://news.yahoo.com/argentine-train-crash-kills-least-40-hurts-550-160437869.html|access-date=22 February 2012|newspaper=Yahoo.com|date=22 February 2012}}</ref> The buffer stops' hydraulic components were found to be disabled<ref>{{Cite web |date=2022-02-22 |title=10 años de la tragedia ferroviaria de Once en Argentina |url=https://cnnespanol.cnn.com/2022/02/21/10-anos-tragedia-once-argentina-orix/ |access-date=2024-05-24 |archive-url=https://web.archive.org/web/20220222194906/https://cnnespanol.cnn.com/2022/02/21/10-anos-tragedia-once-argentina-orix/ |archive-date=2022-02-22 |quote=[las pericias] constataron [...] que los paragolpes no contaban con su sistema hidráulico en funcionamiento [...]}}</ref> and did not absorb the energy of the collision.
* 15 January 2013 – [[Saltsjöbaden]], [[Sweden]] – A train parked with the train control lever at "Full throttle" was set in motion when a cleaner closed the door on a four-car [[Electric multiple unit|EMU]] commuter train in Neglinge depot. It reached 80&nbsp;km/h and demolished a buffer stop at Saltsjöbaden station before [[2013 Saltsjöbanan train crash|crashing into a small apartment block beyond the end of the track]], badly injuring the cleaning lady.<ref name=BBC20130115>{{cite news|url=https://www.bbc.co.uk/news/world-europe-21030211|title=Stockholm train crashed into apartments 'by cleaner'|work=BBC News|date=January 15, 2013}}</ref>
* 13 August 2014 – [[Manila]], [[Philippines]] – A southbound [[MRTC 3000 class]] train of the [[MRT Line 3 (Metro Manila)|MRT Line 3]] lost power while departing [[Magallanes station]], prompting a second train to be sent to push the train to [[Taft Avenue station]]. However, the unpowered train suddenly decoupled while in motion and overshot the retarding buffer at Taft Avenue station. As a result, the train derailed onto [[Taft Avenue]], causing multiple injuries. An investigation by the [[Department of Transportation (Philippines)|Department of Transportation and Communications]] showed that standard coupling procedures were not followed and that the runaway train did not use its [[Train protection system|automatic brake]]s as it was unpowered, adding that the retarding buffer at the station was only designed to handle a maximum speed of {{convert|15|kph|mph|sp=us}}.<ref name="ManilaMRT3Derailment">{{Cite news |last=Camus |first=Miguel |date=August 19, 2014 |title=DOTC: Human error blamed for MRT-3 train accident; 4 train workers face raps |newspaper=[[Philippine Daily Inquirer]] |url=https://newsinfo.inquirer.net/630824/dotc-human-error-blamed-for-mrt-3-train-accident-4-train-workers-face-raps |access-date=December 17, 2022}}</ref>
* 20 March 2015 – [[Uttar Pradesh]], [[India]] – The {{rws|Dehradun}}-[[Varanasi Junction railway station|Varanasi]] ''Janata Express'' derailed near [[Bachhrawan]], resulting in at least fifty-eight deaths and 150 people being injured. The driver reported by radio that the brakes on the train had failed, and that he could not stop the train. It was diverted into a siding and [[2015 Uttar Pradesh train accident|crashed through the buffers at Bachhrawan]].<ref name=NDTV748171>{{cite web |url=http://www.ndtv.com/india-news/train-derails-in-uttar-pradeshs-bachharwan-748171?pfrom=home-lateststories |title=32 Die as Train Derails Near Rae Bareli in Uttar Pradesh, 50 People Injured |first=Niha |last=Mahesh |publisher=[[NDTV India]]|access-date=20 March 2015}}</ref>
* 29 September 2016 – [[Hoboken, New Jersey]] – The [[cab car]] of a NJ Transit [[Pascack Valley Line]] commuter train entering Hoboken Terminal [[2016 Hoboken train crash|overran the buffer block]] on track five at 8:45&nbsp;am. The train continued across the low-level passenger concourse connecting the platforms and slammed into a wall of the terminal building, causing serious structural damage. One person was killed and more than 100 were injured.
* 2 November 2020 - [[De Akkers metro station]] - a train empty of passengers on the [[Rotterdam Metro]] crashed through the [[buffer stop]] at the end of the sidings beyond the station. The sidings are built on a viaduct projecting out over the canal. The lead car of the train came to a partial rest on a 10-metre (33 ft) high whale sculpture erected in front of the sidings, preventing the train from falling over the edge and into the canal below.
* 13 March 2021 – [[Kirkby railway station|Kirkby, United Kingdom]] – A Class 507 electric multiple units operated by Merseyrail [[Kirkby train crash|collided with the buffer stop]]. The only injury was the driver of the train. The cause was found to be that the driver was using a mobile phone while he was driving. The distraction led him to enter the station at excessive speed. He was fired and prosecuted, pleading guilty to a charge of endangering the safety of people on the railway.

== See also ==
{{div col|colwidth=23em}}
* [[Buffer (rail transport)]]
* [[Catch points#Sand drag|Catch points]]
* [[Cushioning]]
* [[Derail]]
* [[List of rail accidents]]
* [[Retarder (railroad)]]
* [[Shock absorber]]
* [[Wheel chock]]
{{div col end}}

== References ==
{{reflist}}

== External links ==
{{Commons category}}
* [https://web.archive.org/web/20120428181120/http://www.arhsvic.org.au/node/55 Book about Buffer Stops in Victoria]

{{Rail tracks}}

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[[Category:Railway buildings and structures]]