BS EN 15551:2009+A1:2010

This European Standard defines the requirements for buffers with 105 mm, 110 mm and 150 mm stroke for vehicles or units which use buffers and screw coupling at the coupling interface with other interoperable rolling stock. It covers the functionality, interfaces and testing procedures, including pass fail criteria, for buffers.

NOTE Typically, buffers with a stroke of 105 mm are used on freight wagons and locomotives, buffers with a stroke of 110 mm are used on coaches and locomotives and buffers with a stroke of 150 mm are used on freight wagons.

It defines the different categories of buffers, the space envelope, static and dynamic characteristics and energy absorption.

It includes a calculation method to determine the minimum size of the buffer head to avoid override between buffers.

It defines the static and dynamic characteristics of the elastic systems.

It also defines the requirements for buffers with integrated crash elements (crashworthy buffers) for tank wagons only according to RID.

The requirements of this European Standard also apply to locomotives and passenger coaches which have to meet the crashworthiness requirements of EN 15227 for buffers in normal service only. The properties for the energy absorbing function are defined in EN 15227 and the requirements specified in Clause 7 for tank wagons according to RID are not applicable to locomotives and passenger coaches.

Diagonal buffers are excluded from this European Standard.

For vehicles which have to comply with crashworthiness requirements (locomotives, cab cars or passenger coaches according to EN 15227, tank wagons according to RID), typically crashworthy buffers (buffers with a deformable housing and/or the need for an opening in their mounting flange) or buffers which form part of a combined system consisting of a special buffer (e.g. middle flange buffer) and a deformation element are used. For these types of buffers, interoperability is possible, but interchangeability with freight wagon buffers is not required, and therefore the requirements of 5.2 (Fixing on vehicle and interchangeability), 5.3 (Buffer dimensions) do not apply, those of 5.4 (mechanical characteristics of buffers) and 5.6 (marking) apply with restrictions.