scope:

This standard covers all ballasted flat bottom and bull head track (continuous welded rail, long welded rail and short rail) and conductor rail.

Subject to the length limits given in standard S1157, short lengths of CWR do not require stressing. Requirements in this standard regarding stressing, SFT and CRT do not apply to this "unstressed welded rail".

Purpose 

The purpose of this standard is to describe the actions necessary to prevent track buckling and distortion, by ensuring that:

a) rail is maintained stress-free within the nominated stress-free temperature range;

b) track is maintained with adequate lateral stability;

c) track is maintained adequately to resist fracture of rail or fishplates at low rail temperatures;

d) maintenance activities during periods of high or low rail temperature do not jeopardise track stability. 

This standard sets requirements for track monitoring and speed restrictions in hot weather. 

This standard also includes the minimum action required in the event of a track buckle occurring.

This standard does not cover rail stressing methods in detail. Instead, reference is made to Network Rail standard NR/L2/TRK/3011 where this is applicable to LU track.