scope:

The Supplementary Instructions contained in this catalogue have the same status as the Company Standard to which it refers.

The Supplementary Instructions only applies to the issue number of the Company Standards quoted.

The Supplementary Instructions will be superseded upon the publication of the revised Company Standards to which it relates

Purpose

This catalogue contains Supplementary Instructions when maintenance is directly managed internally within Network Rail the existing Company Standard to which it pertains will not be wholly appropriate. The changes required are minor and there is no material change to the technical requirements of the Company Standard. The changes are to be considered made to the existing Company Standard published by Business Standards only where maintenance is undertaken directly by Network Rail employees.