World Library  
Flag as Inappropriate
Email this Article

Buffer (rail transport)

Article Id: WHEBN0002806112
Reproduction Date:

Title: Buffer (rail transport)  
Author: World Heritage Encyclopedia
Language: English
Subject: Bavarian E I, Bavarian S 3/6, Railway coupling, Glossary of rail transport terms, North Staffordshire Railway
Collection: Locomotive Parts, Rail Technologies
Publisher: World Heritage Encyclopedia

Buffer (rail transport)

Cutaway model of a buffer
A pneumatic buffer with sections cut away

A buffer is a part of the buffers-and-chain coupling system used on the railway systems of many countries, among them most of those in Europe, for attaching railway vehicles to one another.

Fitted at the ends of the vehicle frames, one at each corner, the buffers are projecting, shock-absorbing pads which, when vehicles are coupled, are brought into contact with those on the next vehicle. The draw chain used between each pair of vehicles includes a screw which is tightened after coupling to shorten the chain and keep the buffers pressed together. Such is known as a 'screw coupling'. Historically, coupling chains were no more than that, a short length of heavy chain (typically three links long) with no adjustment. These would result in a 'loose-coupled train' in which the buffers of adjacent vehicles would only touch when the coupling chain was fully slack, such as when being pushed or going down hill.

Although the buffers in the very earliest days of railways were rigid (dumb buffers), they soon came to be spring-loaded, while those fitted to modern locomotives and rolling stock incorporate oleo-pneumatic shock absorbers.


  • Shape 1
  • Buffer stops 2
  • Collisions 3
  • See also 4


The original English buffers were the same on each side, so that there was a small tendency for buffers to slide off each other. German railway buffers are flat on one side and convex on the other to reduce this tendency to slide off.

Buffer stops

A buffer stop in Italy

Dead-end sidings are often fitted with buffer stops to prevent vehicles running off the end of the track. These may consist of a simple transverse beam fixed at buffer height but the buffer stops at passenger stations can be elaborate hydraulic installations capable of absorbing a considerable amount of energy.

Friction buffer stops are clamped 'loosely' to the rails, and when hit by a train that fails to stop correctly, move with the train for perhaps 30 m (98 ft) scraping the top of the rails, which absorbs considerable energy.


In violent collisions, the buffers of adjacent carriages may become displaced relative to one another, allowing the carriages to telescope which is very dangerous. The risk of this can be reduced if the buffers (or fake buffers) have corrugations that grip each other and prevent the buffers becoming displaced and so leading to telescoping.

See also

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.