scope:

This guidance applies to rolling stock components.

This document deals with the physics of crack behaviour to a level sufficient to inform non-engineering managers about the validity of decisions taken to manage and control cracks to allow continued safe running. A basic familiarity with London Underground rolling stock is assumed. This guidance document should be read as a supporting reference to Section A3.1.11 of Category 2 Standard S2180. There are a number of such procedures in existence and this document better informs their use when the sub-standard condition relates to fracture defects. The focus is on dealing with cracks after their discovery rather than on design for avoidance.

Purpose

The purpose of this document is to provide guidance and support to the process of managing fracture defects (cracks) discovered in rolling stock components. Dealing with cracks should be seen as a 'business as usual' activity.