Last update 12 February 2021
Please follow these links for:
| Code | Line Name | Route Availability (RA) |
|---|
| GW100 | Paddington to Penzance (via Box) Replaced by GW103, GW105 and GW108 from November 1999 | |
| GW103 | Paddington to Uffington Replaced part of GW100 from November 1999 | 8 |
| GW105 | Uffington to Fordgate (via Box) Replaced part of GW100 from November 1999 | 8 |
| GW107 | Worle Junction to Uphill Junction (via Weston-super-Mare) Replaced GW550 from November 1999 | 8 |
| GW108 | Fordgate to Penzance Replaced part of GW100 from November 1999 | Note 1 |
| GW110 | Old Oak Common West to South Ruislip (exclusive) | 8 |
| GW117 | Greenford East Junction to Greenford South Junction | 8 |
| GW130 | Acton Wells Junction (exclusive) to Acton East | 8 |
| GW174 | West Ealing to Greenford West Junction | 8 |
| GW175 | Greenford (LUL) Bay Junction to Greenford Station | 8 |
| GW176 | Drayton Green to Hanwell Junction | 8 |
| GW178 | Southall to Brentford Goods | 8 |
| GW180 | Heathrow Airport Junction to Heathrow Terminal 4 Replaced by new GW180 from 10th April 2007 | 8 |
| GW180 | Heathrow Airport Junction to Heathrow Terminals 4 and 5 Replaced old GW180 from 10th April 2007 | 8 |
| GW182 | West Drayton to Colnbrook | 8 |
| GW184 | Slough to Windsor & Eton | 3 RA6 to 16 April 2011 |
| GW185 | Maidenhead to Marlow | 6 |
| GW187 | Twyford to Henley-on-Thames | 4 |
| GW190 | Reading Spur Junction to Reading New Junction | 8 |
| GW195 | Reading Southern Junction to Reading East Junction (Reading Low Level Line) From 6 June 2015 | 8 |
| GW200 | Didcot to Heyford (exclusive) | 8 |
| GW210 | Reading to Wokingham | ? |
| GW220 | Reading Oxford Road Junction to Reading West Junction | 8 |
| GW225 | Reading Caversham Road Junction to Oxford Road Junction (Reading Feeder Lines) | 8 |
| GW240 | Didcot East Junction to Didcot North Junction (via Avoiding Line) | 8 |
| GW250 | Foxhall Junction to Didcot West Curve Junction | 8 |
| GW254 | Appleford stone terminal branch | ? |
| GW260 | Kennington Junction to Morris Cowley | 7 |
| GW276 | Bicester Eastern Perimeter Road Level Crossing to Oxford North Junction Replaced by GW277 from 14 September 2015 | 7 |
| GW277 | Oxford North Junction to Oxford Parkway (exclusive) Replaced GW276 from 14 September 2015 | 8 |
| GW300 | Abbotswood Junction to Stoke Works Junction (via Worcester Shrub Hill) Replaced by MD900 from 27 March 2021 | 8 |
| GW310 | Wolvercot Junction to Norton Junction Replaced by MD910 and new GW310 from 27 March 2021 | 7 |
| GW310 | Wolvercot Junction to Pershore Replaced old GW310 from 27 March 2021 | 7 |
| GW317 | Honeybourne Ground Frame to Long Marston | 7 |
| GW340 | Worcester Shrub Hill to Shelwick Junction Replaced by MD940 from 27 March 2021 | 7 |
| GW350 | Worcester Tunnel Junction to Henwick Replaced by MD950 from 27 March 2021 | 7 |
| GW370 | Droitwich Spa to Cutnall Green Merged into MD430 from 27 March 2021 | 8 |
| GW400 | Barnt Green (exclusive) to Westerleigh Junction (via Dunhampstead) Replaced by GW401 and part of MD306 from 21 October 2017 | 8 |
| GW401 | Ashchurch (inclusive) to Westerleigh Junction Replaced GW400 from 21 October 2017 | 8 |
| GW425 | Berkeley Road Junction to Sharpness | 6 |
| GW430 | Yate Middle Junction to Tytherington Replaced by new GW430 from 24th July 2004 | 8 |
| GW430 | Yate Middle Junction (outgoing or incoming lines) to Tytherington Replaced old GW430 from 24th July 2004 | 8 |
| GW440 | Yate South Junction to Westerleigh | 8 |
| GW450 | Stoke Gifford Junction to Bristol East Junction | 8 |
| GW451 | Filton Junction to Filton West Junction (Filton Curve) | 7 RA8 to 14 January 2012 |
| GW454 | Severn Beach to Narroways Hill Junction | 7 |
| GW456 | Easton Road Junction to Barrow Road | ? |
| GW468 | South Marston Junction to Keypoint Euroterminal | ? |
| GW470 | Highworth Junction to Rover Sidings | 8 |
| GW480 | Swindon to Standish Junction | 8 |
| GW490 | Gloucester Yard Junction to Horton Road Junction | 8 |
| GW500 | Reading to Cogload Junction (via Westbury and Frome Avoiding Lines) | 8 |
| GW510 | Westbury North Junction to Bathampton Junction | 8 |
| GW520 | Westbury East Loop Junction to Hawkeridge Junction | 8 |
| GW521 | Westbury East Loop Junction to Hawkeridge Junction Believed to be listed in error | |
| GW523 | Thingley Junction to Bradford Junction | 8 |
| GW528 | Bristol North Somerset Junction to Bristol West Junction (via St Philips Marsh) | 8 |
| GW530 | Bristol North Somerset Junction to Dr Days Junction | 8 |
| GW540 | Filton Junction to Patchway Junction | 8 |
| GW548 | Parson Street Junction to Portbury | 8 |
| GW550 | Worle Junction to Uphill Junction (via Weston-super-Mare) Replaced by GW107 November 1999 | 8 |
| GW560 | Heywood Road Junction to Fairwood Junction (via Westbury) | 8 |
| GW570 | Clink Road Junction to Blatchbridge Junction (via Frome) | 8 |
| GW572 | Frome North Junction to Whatley Quarry | 6 |
| GW580 | East Somerset Junction to Cranmore | 8 |
| GW590 | Castle Cary to 130m 00ch (Weymouth Line) | 8 |
| GW600 | Wootton Bassett Junction to Pilning Replaced GW800 from November 1999 | 8 |
| GW600 | Reading New Junction to Reading Spur Junction Believed to be listed in error | 8 |
| GW602 | Norton Fitzwarren Junction to Norton Fitzwarren WSR boundary | 8 |
| GW606 | Cowley Bridge Junction to Barnstaple | Note 2 |
| GW608 | Crediton Junction to Coleford (Meldon Line) | 6 |
| GW609 | Coleford to Meldon | 6 |
| GW610 | Crannaford Level Crossing (incl) to Exeter St Davids | 8 |
| GW611 | Exmouth Junction to Exmouth | 6 |
| GW613 | City Basin Junction to Marsh Barton | 8 |
| GW618 | Newton Abbot East Junction to Heathfield | 6 |
| GW620 | Newton Abbot West Junction to Goodrington Carriage Sidings (Paignton) | 6 |
| GW621 | Paignton to Goodrington Sidings | 6 |
| GW626 | Tavistock Junction to Marsh Mills | 8 |
| GW628 | Laira Junction to Cattewater (via Speedway Junction) Replaced by new GW628 from 22 January 2011 | Note 3 |
| GW628 | Laira Junction/Lipson Junction to Cattewater Replaced old GW628 from 22 January 2011 | Note 3 |
| GW629 | Laira Junction to Mount Gould Junction via Maintenance Depot | 7? |
| GW630 | Lipson Junction to Speedway Junction | 7 |
| GW637 | St Budeaux Junction to Gunnislake | Note 4 |
| GW640 | Liskeard to Looe (via Coombe) | 4 |
| GW642 | Coombe (exclusive) to Moorswater | 4 |
| GW650 | Lostwithiel to Fowey Carne Point | 6 |
| GW660 | Par to Newquay | Note 5 |
| GW661 | St Blazey to Par Harbour | 6 |
| GW672 | Burngullow to Parkandillack | Note 12 RA6 to 14 January 2012 |
| GW680 | Penwithers Junction to Falmouth | 6 |
| GW690 | St Erth to St Ives | 5 |
| GW700 | Gloucester Barnwood Junction to Severn Tunnel Junction Replaced by CY240 from 2016 | Note 6 |
| GW704 | Wye Valley Junction to Tidenham Quarry | ? |
| GW705 | Caldicot Level Crossing Ground Frame to Sudbrook Code deleted 8 November 2008 | 6 |
| GW710 | Llanwern Works East Connection to Llanwern Works West Connection (via British Steel Service Lines) | 8 |
| GW720 | Uskmouth to East Usk Junction | 8 |
| GW730 | Sutton Bridge Junction (exclusive) to Newport Maindee West Junction Replaced by new GW730 from 4 August 2001 | 8 |
| GW730 | Shrewsbury Severn Bridge Junction to Newport Maindee West Junction Replaced old GW730 and MD820 from 4 August 2001 | 8 |
| GW731 | Abbey Foregate to Ruabon Replaced part of MD801 from 4 August 2001 | 8 |
| GW732 | Abbey Foregate to English Bridge Junction Replaced MD815 from 4 August 2001 | 8 |
| GW733 | Sutton Bridge Junction to Aberystwyth Replaced MD825 from 4 August 2001 | Note 7 |
| GW734 | Dovey Junction to Pwllheli Replaced MD830 from 4 August 2001 | 5 |
| GW735 | Shrewsbury Crewe Junction to Nantwich Replaced MD835 from 4 August 2001 | 8 |
| GW736 | Gobowen South to Llanddu Junction Replaced MD840 from 4 August 2001 | 5 |
| GW740 | Maindee East Junction to Maindee North Junction | 8 |
| GW750 | Hereford Brecon Curve Ground Frame to MEB Siding | 8 |
| GW770 | Ebbw Vale South Ground Frame to Gaer Junction (Western Valley Line) Replaced by new GW770 from 30 November 2007 | 8 |
| GW770 | Ebbw Vale Parkway to Gaer Junction (Western Valley Line) Replaced old GW770 from 30 November 2007; replaced by new GW770 from 10 May 2015 | 5 RA8 to 25 April 2009 |
| GW770 | Ebbw Vale Town to Gaer Junction (Western Valley Line) Replaced old GW770 from 10 May 2015 | 5 |
| GW773 | Machen Quarry to Park Junction | 6 |
| GW780 | Ebbw Junction to Park Junction | 8 |
| GW784 | Alexandra Dock Junction to 160m 27ch (boundary with ABP Newport Docks) | 8 |
| GW790 | Pengam Junction to 4m 54ch (boundary with ABP Cardiff Docks) Replaced by new GW790 from 29 June 2015 | 7 |
| GW790 | Pengam Junction to Tidal Sidings Replaced old GW790 from 29 June 2015 | 7 |
| GW800 | Wootton Bassett Junction to Pilning Replaced by GW600 November 1999 | 8 |
| GW810 | Rhymney to Queen Street North Junction | 6 |
| GW819 | Penrhiwfelin Ground Frame to Ystrad Mynach North Line disconnected by 19 December 2007: unclear whether code deleted at same time | ? |
| GW820 | Cwmbargoed to Ystrad Mynach South | 8 |
| GW828 | Coryton to Heath Junction | 6 |
| GW830 | Merthyr Tydfil to Barry Island (via Cardiff Queen Street) | Note 8 |
| GW834 | Hirwaun to Abercynon | 6 |
| GW835 | Treherbert to Pontypridd Junction | 6 |
| GW839 | Queen Street South Junction to Cardiff Bay | 6 |
| GW840 | Radyr Junction to Cardiff Radyr Branch Junction (via City Lines) | 8 |
| GW850 | Leckwith Loop South Junction to North Junction | 8 |
| GW860 | Penarth Curve North Junction to Penarth Curve South Junction | 8 |
| GW864 | Cogan Junction to Penarth | 6 |
| GW870 | Barry to Bridgend Barry Junction (Vale of Glamorgan Line) | 8 |
| GW871 | Ford's Junction to Waterton | 8 |
| GW873 | Llantrisant East Ground Frame to Cwm Llantwit | ? |
| GW874 | Bridgend Llynfi Junction to Llynfi Replaced by new GW874 by 2016 | 6 |
| GW874 | Bridgend Llynfi Junction to Maesteg Replaced old GW874 by 2016 | 6 |
| GW875 | Tondu to Pontycymmer | ? |
| GW877 | Tondu to Port Talbot Docks (Ogmore Vale Extension) | 6 |
| GW878 | Newlands Loop Junction to Newlands Junction | 8 |
| GW887 | Margam Yard Junction to Margam Middle Junction | 8 |
| GW888 | Margam Moors Junction to Margam Abbey Works East Junction | 8 |
| GW890 | Court Sart Junction/Up Flying Loop Junction to Morlais Junction | 8 |
| GW892 | Jersey Marine Junction South to Glyn Neath | 6 |
| GW893 | Onllwyn to Neath & Brecon Junction | 6 |
| GW894 | Jersey Marine Junction North to Jersey Marine Junction South | 8 |
| GW897 | Grovesend Colliery Loop Junction to Hendy Junction | 6 RA8 to 14 January 2012 |
| GW900 | Pilning to Fishguard Harbour | Note 9 |
| GW906 | Swansea Loop East Junction to Swansea Loop West Junction | 7 |
| GW910 | Craven Arms to Llandeilo Junction (Central Wales Line) | Note 10 |
| GW915 | Gwaun-Cae-Gurwen to Pantyffynnon | 5 |
| GW923 | Cwmmawr to Kidwelly | 8 presumed |
| GW930 | Carmarthen Junction to Carmarthen Station | 8 |
| GW940 | Carmarthen Station to Carmarthen Bridge Junction | 8 |
| GW950 | Whitland to Pembroke Dock Replaced by CY1540 from 2012 | Note 11 |
| GW960 | Clarbeston Road to Milford Haven | 8 |
| GW970 | Gulf Oil Branch Junction to Waterston Gulf Oil Refinery | 8 |
| GW980 | Herbrandston Junction to Robeston Amoco Sidings | 8 |
| GW990 | Trecwn to Letterston Junction | ? |
| GW1000 | All Lines | n/a |
| GW4501 | Stoke Gifford Junction to Bristol Bulk Handling Terminal | 7 |
| GW5001 | Beechgrove Ground Frame (incl) to Westbury North Junction | 8 |
| GW5401 | Filton West Junction to Patchway Junction (Patchway Chord) | 7 or 8 conflicting information |
| GW6135 | Exeter Railway Junction to Alphington Road | ? |
| GW8001 | Long Dyke Junction to 0m 33ch (boundary with ASW Castle Works) | ? |
| GW8901 | Jersey Marine Junction South to Jersey Marine | 6 |
| GW9001 | Landore Junction to Swansea | 7 |