scope:

This document applies to all signalling schemes and detailed design where the usage of lines is altered or alterations are made to the layout.

This specification details the requirements to provide trapping protection for passenger lines against the movement of unattended vehicles. It details the circumstances whereby an overrun to a dead-end or traps may be used in lieu of an overlap. It also details the risks and associated control measures to be considered when providing trap points or points leading to a dead-end (e.g. sand drag).

This specification shall be applied whenever sidings are connected directly, or indirectly, to a passenger line, whenever a line is reclassified from freight to passenger use or where the removal of existing trap points is considered.

This specification is less prescriptive than the requirements in NR/L2/TRK/2049 for the provision of trap points and a derogation has been granted to amend the track standard in line with this specification. The requirements relating to the design of trap point equipment remain in NR/L2/TRK/2049.

NOTE This specification does not cover run back catch points provided on a running line to derail a portion of a divided train on a gradient.

Purpose

This section forms part of the Signalling Principles Handbook (NR/L2/SIG/30009) and is to be read in conjunction with the other sections of the handbook.

This section details Network Rail's policy on provision of Trapping Protection and comprises mandatory sections, statements of best practice (which shall be followed unless an alternative can be demonstrated to be beneficial to the company and no less safe), and guidance on historical practices (which are not to be applied to new works but provide information on previous standards or their interpretation).

The requirements for the provision of trap points (or equivalent) and their application to provide trapping and overrun protection is contained in a number of documents, both internal and external to Network Rail. This module brings all the requirements together in a consistent manner. The various contradictions between standards are thereby eliminated.