British Railways Mark 1 - Safety

Safety

The steady building of Mark 1 stock to replace earlier vehicles was praised by the Chief Inspecting Officer of Railways, Lt Col I.K.A. McNaughton (Chief Inspecting Officer of Railways, Dept of Transport), in the Sir Seymour Biscoe Tritton lecture to the Institute of Mechanical Engineers in 1977. Speaking of the fall in fatalities since 1955, he put forward his opinion that a major factor in this improvement was "the introduction in 1951 of the BR standard Mark 1 passenger coach, which, over a period of about ten years, replaced pre-war designed rolling stock on most principal routes. The damage-resistant qualities of this all-steel coach, mounted on a 200 ton end-load resistant underframe and fitted with buckeye couplings, have been evidenced time and time again. Only in a small number of very destructive accidents has serious body damage of the kind that inevitably leads to fatal accidents been observed and there have been several remarkable instances of high-speed derailments in which no personal injuries have occurred."

Although construction of Mark 1 passenger stock ended in 1963, multiple units and non-passenger carrying stock based on the Mark 1 design continued to be built until 1974.

The Hidden report into the 1988 Clapham Junction rail accident accepted that withdrawal of the Mark 1 units was not practical and the design was safe: "The inventory of Mark I coaching stock is large, and much of it has not reached an end of economic life, nor will do so for another decade or more. Mark I vehicles have good riding qualities, and are not intrinsically lacking in collision resistance" British Rail was still using multiple units with underframes that had been constructed before World War II, and these had priority for replacement.

During the late 1990s Mark 1 stock began to reach the end of its design life and it was becoming comparatively less safe to other, more modern, high speed passenger vehicles. The UK Health and Safety Executive issued instructions in 1999 to withdraw all Mark 1 coaches and multiple units based on that design by the end of 2002 "unless rebodied or modified to prevent, or reduce the potential for, overriding in the event of a collision". A proposed modification to extend mainline use beyond 2002 at the time of the 1999 HSE instruction was 'cup and cone', however trials were inconclusive and deemed expensive in comparison with the safety benefits. In October 2002 the Health and Safety Executive extended the permitted use of Mark 1 based rolling stock until 31 December 2004 with the proviso: "The exemptions are subject to conditions, namely that any Mark 1 rolling stock operated by the TOCs after 31 March 2003 must form part of a train fully fitted with a train protection system." The UK Train Protection & Warning System (TPWS) greatly reduces the chances of collisions.