scope:

This document mainly covers railway signalling wires and cables with copper conductors. The conductors in wires and cables with natural rubber insulation are tinned and surrounded by an external layer of polychloroprene. The colours mentioned are those most commonly found, but some types are available in other colours. Known problems with cables of other types are mentioned. Except where specially mentioned, references to 'cables' may be taken as also applying to wires (i.e. single insulated conductors without an overall sheath).

PURPOSE

This document provides an understanding of problems with cable and wiring insulation degradation that have been encountered on Railtrack Signalling Infrastructure, together with relevant technical information and the historical background to the problem. Some notes on inspection techniques, alterations to affected wiring and some miscellaneous cable problems are included in the appendices.