Standard
NR/L2/SIG/19812
Cross Track Cable Management
Issue 2, 05 December 2020
How any cable (signalling, telecoms or third party) gets across the track: the ranked choice of under-track crossing, over-track structure, hollow or ducted sleepers, cleats or orange pipe, the limits on each, and rules for fixing cables to overline structures added after the Abergavenny OTX failure.
Clause map — what each clause deals with
| 1 | Purpose | Sets out why cross-track cable installation matters: protecting cables and the public, avoiding sagging cables, and keeping mechanised track maintenance unobstructed |
| 2 | Scope | Covers every cable crossing Network Rail tracks whoever owns it, including station and third party cables, for renewals, enhancements and maintenance |
| 3 | Definitions | Explains terms such as cross track cable, main cable, tail cable, UTX, OTX, orange pipes, and major versus minor renewals and enhancements |
| 4 | Acronyms | Abbreviation list for the crossing methods (UTX, OTX, HS, DSC, DSS, CC, OP) and related systems |
| 5 | Policy | Cables must not lie loose in the track; the crossing method is picked from the preference tables considering work type, track category, electrification and cable type and function |
| 6 | Cable management method preference | Lists the acceptable crossing methods and the ranked preference tables for third rail and for 25kV or non-electrified lines; orange pipe is last resort and needs RAM-endorsed justification |
| 7 | Cable management between Sleeper(s), Bearer(s) and the Through Route | Routing cables from the sleeper to the cess or troughing: keep clear of the tamping zone, keep runs short, protect them on the ballast and do not bury them |
| 8.1.1 | Audio frequency track circuits | Named audio frequency track circuit types must not have their track connections run through hollow or ducted steel sleepers because of impedance effects |
| 8.1.2 | Hollow steel sleepers | Hollow steel sleepers are not to carry earth bonds or traction power cables |
| 8.2 | Third rail areas - hollow steel sleepers | On DC third rail lines hollow steel sleepers are avoided for cables due to electrolysis, except where part of point machine or hot axle box detector kit |
| 8.3 | Track specific constraints | Points to the track design standard NR/L2/TRK/2102 for track-related constraints |
| 9.1 | Orange Pipes | Keep orange pipe use minimal and out of bays that block maintenance, such as near rail joints, narrow bays or next to other obstructions; never on new S&C |
| 9.2 | Key features of sleepers | Explains the feature columns used to compare type-approved cable management sleepers, such as depth, weight, fastening, cable capacity and PADS numbers |
| 9.2.1 | Ducted / Asymmetric Sleepers | Ducted concrete sleepers suit small numbers of cables, asymmetric ones can go in beside existing cables without disconnection; guard cables under the rail |
| 9.3 | Approved cleats | Use type-approved cleats with the specified fixings on concrete, nails or screws on timber, cables run neatly along the sleeper centre |
| 9.4 | Approved cable guards | Cable guards are required wherever a cable passes under the rail; PADS numbers given per rail section |
| 9.5 | Over-Track crossings | Rules for cables on footbridges and gantries: no adding to full or poor trays or existing cables, supported transitions, RAM and gauging approval, containment hierarchy, vandalism and theft |
| 9.6 | Undertrack crossings | Points to NR/L2/CIV/044 for planning, design and construction of under-track crossings |
| Appendix A | Prohibited cable fixing diagram | Diagram of the zones on an overline structure where cables and containment must not be fixed without approval |
| Appendix B | Typical track layouts | Illustrative track layout and an example of cables cleated to sleepers |
| Appendix C | Key features of cable management sleepers | Comparison table of approved cable management sleepers by manufacturer with depth, weight, fastening, cable capacity, acceptance and PADS references |
| Appendix D | Photos of a variety of cable management applications | Photos of cable guards, hollow, ducted and asymmetric sleepers and cables cleated to concrete sleepers |
| Appendix E | Indicative photos of cable containment in over track crossings (OTX) | Good and poor practice photos of open cable trays on over-track structures, such as unsupported exits, plastic ties and bend radius faults |