FTN survey specification
SP FTN (SU) 001
Survey of Cable Routes
Issue 10.2, Feb 2009 · FTN D&D specs & typical drawings
The FTN cable and cable route survey specification: what a surveyor must record about existing troughing, manholes, crossings and buildings, how to decide renovate versus new route or DI-SAC, and how to survey for fibre and copper cable lengths, joints and cabinets.
Clause map — what each clause deals with
| 1 | Implementation | Supersedes the previous issue; effective from date of issue. |
| 2 | Disclaimer | Standard Network Rail disclaimer. |
| 3 | Supply | Where to obtain copies. |
| 4 | Abbreviations | Long abbreviation list including BOP, COSS, DI-SAC, FTE, GLT/SCT, OmniCom, SPT, TEPE, UFmX, UFtX, UTX, URX. |
| 5 | Purpose | Why the survey is done, its two aims (condition/capacity and design input), renovate-vs-parallel-route philosophy, 90 mph line speed classification, long copper section conductor note. |
| 6 | Scope of Works | Deliverable format, civils approvals, nominal section length, fragile cables, asbestos, utility clearances, full list of items to record, survey kit, and cable length allowances. |
| 7 | Performance Requirements for Cable Routes | How to decide new route vs renovation using the appendix flowcharts, lid tilting approach, DI-SAC as a route option, avoiding new UTXs, hollow sleepers banned. |
| 7.1 | Use of OmniCom for Surveying | When and how track video can replace trackside survey, what to know beforehand, and the list of things it can be used to assess. |
| 7.2 | Route Fill | Lid lifting interval and T-pieces to assess spare capacity; what to note when route is fully buried. |
| 7.3 | Replacement of Concrete Items | Criteria for replacing or cutting damaged troughs and lids, photos of acceptable/unacceptable damage, missing/undersized/overlapping lids, upturned lids, locking lids for vandal areas. |
| 7.4 | Lift and Relay, and Realignment of Route | Purposes of relaying/realigning and the parameters that apply when renovation is chosen. |
| 7.4.1 | Lift and Relay Route | When to record lift and relay versus ballast clearance or ballast boards, based on surrounding ground/ballast levels. |
| 7.4.2 | Realignment of Route | When to record realignment and when to consult the Territory Track Engineer about ballast shoulder. |
| 7.4.3 | Route Support | Route support on slopes, galvanised supports, ramped supports over catch pits, inspection of existing supports, photos required. |
| 7.5 | Buried Troughing Routes | No pulling or rodding through buried troughing; replacement with UTX where full; recording directly buried cables and crossings. |
| 7.6 | Ballast Boards | When to record ballast boards, their construction, stacking height limits, Form A/B threshold, not combined with lift and relay. |
| 7.7 | Route Transitions | Recording transition units where new route meets other troughing including imperial GLT. |
| 7.8 | New Cable Route | Positioning of new route relative to track, datum plates, traction bonds, minimum/preferred rail distances, reduced clearance concession, triggers for new route (obsolete, asbestos, none, full). |
| 7.9 | T-Pieces | Where T-pieces are needed (joint bays, BOPs, cabinets) and sizing. |
| 7.10 | Machine Cut Concrete Troughing and Lids | How to count machine cut items. |
| 7.11 | Ballast and Vegetation Clearance | Depth bands for ballast cover, other obstruction categories (shoulder, bank slip), and light/medium/heavy vegetation definitions, measured per route metre. |
| 7.12 | Manholes | Gas check before entry; repairs, lid/frame replacement, materials, climbing aids, rebuild and renovate criteria, new manhole triggers, platform/UTX/URX manholes, keys, duct seals at buildings. |
| 7.13 | Red/Green Zone Working | Recording green vs red zone work, red zone prohibited, and which manhole works imply possession/night work. |
| 7.14 | GRP, GRC, uPVC | Non-concrete troughing for vertical, wall-top and parapet routes; asbestos cement replacement; recording existing wall routes and fixings. |
| 7.15 | Retaining Walls | When to record new, repaired or rebuilt retaining walls, construction standard and Form A/B threshold. |
| 7.16 | Earthing Rods for Lineside Cabinets | Do not open existing cabinets; earth rods only at DSL repeater cabinets, cabinet model compatibility. |
| 7.17 | Concrete Bases | REB base drawing, pre-cast bases for cabinets and BOPs, siting criteria to reuse tail cables, avoiding vandalism areas, when hard-standing is needed. |
| 7.18 | Exchanges and Apparatus Rooms | Recording occupied/free ducts into buildings, no allowance for future cables, diverse entries and sketches. |
| 7.19 | Joint Bays | Parallel joint bays for copper joints and perpendicular joint bays or Stakka boxes for fibre joints, knockout sill protection, handrails for green zone, possession note. |
| 7.20 | Routes Through Stations | Platform duct capacity needed, rodding and proving, test pulls, recording which ducts FTN uses, when a new platform duct route is justified and its manholes. |
| 7.21 | Under Road Crossings / Level Crossings | Assess as for station ducts; when to record a new URX and subsidence reporting. |
| 7.22 | Farm Crossings | Using buried troughing at farm crossings or recording new buried troughing with double lids where vehicles cross. |
| 7.23 | Under Track Crossings | Prefer under-track boring; when to record new 6-way or 4-way UTX; testing S-type UTXs with a test pull; sidings. |
| 7.24 | Foot Crossing Routes | Buried troughing at foot crossings; otherwise as farm crossings. |
| 7.25 | Routes Under Hard Surfaced Walkway or Through Yard | Same approach as farm crossings for buried routes under walkways and yards. |
| 7.26 | Surplus Scrap Material, Recovery and Disposal | Recording scrap by route metre, recovery via road, asbestos disposal. |
| 7.27 | Restricted Working | Noting tunnels, cuttings and restricted areas; tunnel entry only with possession and isolation. |
| 7.28 | Route Obstructions | Recording removal of obstructions such as rails and sleepers. |
| 7.29 | New Roads & Street Works Act | Recording exact distances of manholes and ducts crossing roads, car parks and footpaths for NRSWA records. |
| 7.30 | Cable Route Interfaces with Nodes | Recording GLT or duct interface at node sites per the 1001 to 1004 drawings. |
| 8 | Cable Survey Requirements | Parent clause for the fibre and copper cable surveys. |
| 8.1 | Optical Fibre Cable Survey | Everything the surveyor records for fibre cables. |
| 8.1.1 | General | List of fibre items to record: lengths, pull direction, joints, extra joints at crossings, sheath gaps, spurs, terminations, route separation, building entries. |
| 8.1.2 | Centre to centre cable lengths | Maximise joint spacing, measure centre-to-centre and add section 6 allowances; cables terminate only at nodes, joints are not distribution points. |
| 8.1.3 | Joint Locations | Nominal fibre joint spacing and concession threshold, green zone siting, joint bays vs manholes, tunnel mouth joints, co-siting, spliceless joints near stations/level crossings, DI-SAC caveats. |
| 8.1.4 | Sheath Gaps | Why fibre sheaths are gapped; record positions per SP/FTN(D&D)/005 and 008. |
| 8.1.5 | Core Node Sites | Core nodes need physically diverse cables; meet SP/FTN(D&D)/008 resilience. |
| 8.1.6 | Access Node Sites and Spur Cables | Single vs diverse spurs for SR and DR access nodes, deferral when approvals are missing, what to record for deferred and non-deferred spurs. |
| 8.1.7 | Choice of Optical Fibre Cable Type | The standard cable family (duct, armoured, ZHLS) and DI-SAC construction, where each may be used, subsurface station rule, refer to SP/FTN(D&D)/008 for selection. |
| 8.1.8 | Provision for GSM-R Tunnel Repeaters | Fibre feed for tunnel and stand-alone repeaters: pulled fibre tubing and bundled fibre lengths, joint distance from tunnel mouth, BPE/O closure siting, DI-SAC restriction, trunking. |
| 8.2 | Copper Cable Survey | Everything the surveyor records for copper cables. |
| 8.2.1 | General | List of copper items to record: lengths, pull direction, joints, sheath gaps, cabinets and BOPs, tunnel termination boxes, building entries, electrification, earths, screening conductors, parallelism. |
| 8.2.2 | Choice of Cable Type | Two copper sheath types; refer to RT/E/PS/00015 for cable and SP/FTN(D&D)/009 for pair count and conductor size. |
| 8.2.3 | Centre to centre cable lengths | Maximise joint spacing; copper measurement and the allowances to add for deviation, jointing and terminating. |
| 8.2.4 | Joint Locations | Nominal copper joint spacing and tolerance, joints only at drum ends, heat shrink closures, joint bays vs manholes, vandal protection, tunnel mouths, co-siting. |
| 8.2.5 | Sheath Gaps | Armour gapping to limit induced voltage; record positions per SP/FTN(D&D)/005. |
| 8.2.6 | Distribution Cabinets and BOPs | Siting cabinets and BOPs to keep tail cables short and reuse existing tails, tail length limits, pre-tailed BOPs need joints either side, no through-jumpering. |
| 8.2.7 | Details of Electrification | Record DC or AC, RR vs RC/BT, screening conductor presence, route height and distance from rail. |
| 8.2.8 | Earth Systems | Siting rules for new earth farms and FTEs (distances from feeder stations, substations, sectioning cabins, other earths) and GT/TD INT100. |
| 8.2.9 | Parallelism | Identify where AC feeders or National Grid lines run parallel for long distances; extra screening may be needed. |
| 9 | Deployment of DI-SAC | DI-SAC treated as a route type; selected via flowchart; linked specs for installation, jointing and as-built. |
| 9.1 | General | Installation outcomes DI-SAC must achieve (service life, no obstruction, tamper resistance, straight line, trip hazard), positioning relative to track and troughing, mixing with good troughing. |
| 10 | Deployment of DBS (Discarded) | Sub-duct (DBS/SLD) no longer used as primary protection except short buried runs at crossings. |
| 11 | References | Lists NR/SP/CIV/039, NR/GN/SIG/11210, NR/SP/OHS/011, NR/GN/SIG/11821, SP/FTN(D&D)/004, 005, 008, 009, NR/WI/CIV/143, GE/RT 8024, GI/RT 7008. |
| App A | Survey Spreadsheet | Note on the Excel survey proforma, survey data sheet and Bill of Quantities; contractual BoQ takes precedence. |
| App B | Cable Route Renovation Flowchart | Decision tree: existing route?, fibre only?, line speed over 90, cost per metre thresholds, leading to DI-SAC, new small SCT, new SCT or renovation. |
| App C | Restricted Distance Flowchart | Decision tree for routes closer than the minimum rail clearance: move route, hanger route, platform duct, new route or raise a technical query. |
| App D | SCT Renovation Flow Chart | Decision tree for renovating existing troughing: covered?, capacity?, trough replacement ratio, lid tilting. |
| App E | Route Cost Decision Flow Chart | Decision tree estimating whether renovation cost exceeds the per-metre limit (fibre-only vs copper sections), lift and relay, support, realignment, clearance grades. |
| App F | Troughing Lid Tilting Tool | Photographs of the lid tilting tool (images only, no text). |