Last update 5 July 2021
Please follow these links for:
| Code | Line Name | Route Availability (RA) |
|---|
| SO000 | All lines | n/a |
| SO110 | Victoria Eastern to Ramsgate (via Herne Hill and Chatham) | 8 |
| SO110A | Bickley Junction to Petts Wood Junction | 8 |
| SO110B | Gillingham to Chatham Dockyard | 8 presumed |
| SO115 | Bickley Junction to Petts Wood Junction | 8 |
| SO118 | Gillingham to Chatham Dockyard | 8 presumed |
| SO120 | London Cannon Street to London Bridge | 8 |
| SO125 | London Cannon Street to Metropolitan Junction | 8 presumed |
| SO130 | Charing Cross/Cannon Street to Dover Priory/Eurotunnel interface (via Tonbridge) | 8 To 16 April 2011: Charing Cross bridge down and up slow lines and middle road RA7. From 16 April 2011: Charing Cross - Metropolitan Junction RA4 (some individual lines London Bridge - New Cross also RA4); also from 22 March 2014 to 5 June 2021 Folkestone Central - Folkestone East Staff Halt RA4 |
| SO130A | London Cannon Street to Metropolitan Junction | 8 presumed |
| SO130B | London Cannon Street to London Bridge | 8 |
| SO130C | Tanners Hill Junction to Lewisham Vale Junction | ? |
| SO130D | St Johns Junction to Lewisham Junction | ? |
| SO130E | Parks Bridge Junction to Ladywell Junction | 8 |
| SO130F | Courthill Loop North Junction to Courthill Loop South Junction | ? |
| SO130G | Chiselhurst Junction to St Mary Cray Junction | 8 |
| SO130H | Saltwood Junction to Dollands Moor | 8 |
| SO130J | Continental Junction to Network Rail/Eurotunnel boundary | 8 |
| SO130K | Sevington Loop to Sevington Sidings | ? |
| SO132 | Chiselhurst Junction to St Mary Cray Junction | 8 |
| SO135 | Saltwood Junction to Dollands Moor | 8 |
| SO137 | Continental Junction to Network Rail/Eurotunnel boundary | 8 |
| SO140 | Swanley to Ashford/Sevenoaks | 8 |
| SO140A | Otford Junction to Sevenoaks | 8 |
| SO145 | Otford Junction to Sevenoaks | 8 |
| SO150 | Sittingbourne Western Junction to Sheerness-on-Sea | 8 |
| SO150A | Sittingbourne Eastern Junction to Sittingbourne Middle Junction | 8 |
| SO155 | Sittingbourne Eastern Junction to Sittingbourne Middle Junction | 8 |
| SO160 | Faversham to Dover Priory | 8 |
| SO170 | Tonbridge to Bo Peep Junction | 8 |
| SO180 | Paddock Wood to Strood | 8 |
| SO190 | Not allocated but briefly used in 2015 for New Malden to Shepperton in error (SW190) | |
| SO200 | Ashford to Hastings | 7 |
| SO210 | Appledore to Lydd Town (Goods Line) | 6 |
| SO220 | Ashford to Ramsgate (via Canterbury West) | 8 |
| SO230 | Folkestone East to Folkestone Harbour | 8 |
| SO240 | Buckland Junction to Minster East Junction | 8 Sandwich - Minster South Junction RA4 from 31 August 2013 |
| SO240A | Minster South Junction to Minster West Junction | 8 |
| SO245 | Minster South Junction to Minster West Junction | 8 |
| SO250 | Factory Junction/Battersea Pier Junction/Clapham Junction to Wembley Central | 8 |
| SO250A | Grosvenor Bridge Junction to Factory Junction | 8 |
| SO250B | Battersea Pier Junction to Longhedge Junction | 8 |
| SO250C | Pouparts Junction to Longhedge Junction | 8 |
| SO250D | Falcon Junction to Latchmere Junction (No 1) | 8 |
| SO252 | Pouparts Junction to Longhedge Junction | 8 |
| SO255 | Battersea Pier Junction to Longhedge Junction | 8 |
| SO257 | Falcon Junction to Latchmere Junction (No 1) | 8 |
| SO259 | Grosvenor Bridge Junction to Factory Junction | 8 |
| SO260 | Brixton Junction to Shortlands Junction (Catford Loop) | 8 |
| SO270 | Nunhead to Lewisham Merged into SO330 | 8 |
| SO280 | Farringdon to Herne Hill | 4 |
| SO280A | London Blackfriars to Metropolitan Junction | 4 |
| SO280B | Loughborough Junction to Cambria Junction | 7 |
| SO280C | Loughborough Junction to Canterbury Road Junction | 8 |
| SO282 | London Blackfriars to Metropolitan Junction | 4 |
| SO284 | Loughborough Junction to Cambria Junction | 7 |
| SO286 | Loughborough Junction to Canterbury Road Junction | 8 |
| SO290 | North Kent East Junction to Dartford Junction (via Greenwich) | 8 North Kent East Junction - Charlton RA6 |
| SO290A | Blackheath Junction to Charlton Junction | 8 |
| SO290B | Angerstein Junction to Angerstein Wharf | 8 |
| SO300 | Lewisham Junction to Crayford Creek Junction (via Bexleyheath) | 8 |
| SO300A | Slade Green Junction to Perry Street Fork Junction | 8 |
| SO302 | Slade Green Junction to Perry Street Fork Junction | 8 |
| SO305 | Blackheath Junction to Charlton Junction | 8 |
| SO307 | Angerstein Junction to Angerstein Wharf | 8 |
| SO310 | Hither Green to Rochester Bridge Junction (via Sidcup) | 8 |
| SO310A | Lee Spur Junction to Lee Loop Junction | 8 |
| SO310B | Crayford Spur 'A' Junction to Crayford Spur 'B' Junction | 8 |
| SO312 | Lee Spur Junction to Lee Loop Junction | 8 |
| SO315 | Crayford Spur 'A' Junction to Crayford Spur 'B' Junction | 8 |
| SO320 | Hoo Junction to Grain (Goods Line) | 8 |
| SO330 | Nunhead to Hayes | 8 From 16 April 2011 New Beckenham - Hayes RA4 |
| SO330A | New Beckenham to New Beckenham Junction | 8 |
| SO331 | Courthill Loop North Junction to Courthill Loop South Junction | 8 |
| SO332 | Tanners Hill Junction to Lewisham Vale Junction | 8 |
| SO333 | St Johns Junction to Lewisham Junction | 8 |
| SO334 | Parks Bridge Junction to Ladywell Junction | 8 |
| SO335 | New Beckenham to New Beckenham Junction | 8 |
| SO350 | Grove Park to Bromley North | 8 |
| SO400 | Southfleet Junction to Eurotunnel Interface Replaced by new SO400 | ? |
| SO400 | St Pancras to Eurotunnel Interface | ? |
| SO410 | Stratford International West Junction to Temple Mills International Depot There is some confusion with this code's designation | ? |
| SO410A | Regents Canal Junction to York Way North Junction There is some confusion with this code's designation | ? |
| SO410B | Regents Canal Junction to Cedar Junction There is some confusion with this code's designation | ? |
| SO420 | Ripple Lane CTRL connecting lines There is some confusion with this code's designation | ? |
| SO420 | York Way South Junction to Camden Road Incline Junction There is some confusion with this code's designation | ? |
| SO430 | Ebbsfleet to Springhead Junction There is some confusion with this code's designation | ? |
| SO430 | Stratford International West Junction to Temple Mills International Depot There is some confusion with this code's designation | ? |
| SO440 | Ripple Lane Exchange Lines to Dagenham Junction | ? |
| SO450 | Ebbsfleet West Junction to Springhead Road Junction | ? |
| SO460 | Fawkham Junction to Southfleet Junction | 8 |
| SO470 | Ashford West Junction (AD947 and AD949 Signals) to Ashford International | ? |
| SO480 | Ashford International to Ashford East Junction (AD954 and AD956) | ? |
| SO490 | Dollands Moor West Junction to Dollands Moor Yard (AD759 Signal and AF342 Marker) | ? |
| SO500 | Victoria to Brighton | 8 |
| SO500A | Selhurst Junction to Gloucester Road Junction | 8 |
| SO500B | Copyhold Junction to Ardingly | 8 |
| SO500C | Preston Park to Hove | 8 |
| SO510 | London Bridge to Epsom Downs | 8 |
| SO510A | Sydenham to Crystal Palace | 8 |
| SO510B | Norwood Junction to Windmill Bridge Junction | 8 |
| SO512 | Norwood Junction to Windmill Bridge Junction | 8 |
| SO515 | Selhurst Junction to Gloucester Road Junction | 8 |
| SO520 | Three Bridges to Portsmouth Harbour (via Horsham) | 8 Blackfriars Junction - Portsmouth Harbour platforms 4/5 RA7; Portsmouth Harbour platforms 1/3 RA4 |
| SO520A | Ford Junction to Littlehampton Junction | 8 |
| SO530 | South Croydon Junction to East Grinstead | 6 To 16 April 2011: South Croydon - Selsdon RA8. From 16 April 2011: South Croydon - 12m 40ch RA8; 12m 40ch - Hurst Green RA4 |
| SO540 | Hurst Green Junction to Uckfield | 4 RA6 to 16 April 2011 |
| SO550 | Redhill to Tonbridge | 8 |
| SO560 | Redhill to Guildford | 8 |
| SO570 | Believed not allocated but briefly used for Woking to Guildford in 1999 | |
| SO580 | Copyhold Junction to Ardingly | 8 |
| SO590 | Keymer Junction to Eastbourne | 8 |
| SO600 | Willingdon Junction to Ashford | 7 To 16 April 2011: Willingdon Junction - Hastings RA8. From 16 April 2011: St Leonards - Hastings RA8; Ore - Ashford RA7; remainder RA4. From 20 June 2015: St Leonards - Hastings RA8; Hastings - Ashford RA7; remainder RA4. From 18 August 2018: Willington Junction-Hastings RA8; remainder RA7 |
| SO610 | Southerham Junction to Seaford Considered part of extended SO620 in some documents | 7 |
| SO620 | Brighton to Lewes Considered part of extended SO620 in some documents | 8 |
| SO620 | Brighton to Seaford Considered to include 'old' SO610, SO620 and SO625 in some documents | 8 |
| SO620A | Newhaven Harbour Junction to Newhaven Marine | 7 |
| SO625 | Newhaven Harbour Junction to Newhaven Marine Considered part of extended SO620 in some documents | 7 |
| SO630 | Brighton/Preston Park to Littlehampton | 8 |
| SO632 | Ford Junction to Littlehampton Junction | 8 |
| SO635 | Preston Park to Hove | 8 |
| SO640 | Barnham to Bognor Regis | 8 |
| SO645 | Battersea Park to Peckham Rye (Atlantic Lines) | 8 |
| SO650 | Balham Junction to Beckenham Junction/Norwood Junction | 8 |
| SO650A | Bromley Junction to Norwood Junction | 8 |
| SO653 | Tulse Hill to Leighham Junction | 8 |
| SO655 | Bromley Junction to Norwood Junction | 8 |
| SO658 | Tulse Hill to West Norwood Junction | 8 |
| SO660 | Purley to Caterham | 8 |
| SO660A | Chipstead Line Junction to Tattenham Corner | 8 |
| SO670 | Purley to Tattenham Corner | 8 |
| SO680 | South Bermondsey Junction to Horsham | 8 |
| SO680A | Herne Hill to Tulse Hill | 8 |
| SO680B | Tulse Hill to Leighham Junction | 8 |
| SO680C | Tulse Hill to West Norwood Junction | 8 |
| SO680D | Streatham Junction to Streatham Common | 8 |
| SO680E | Streatham North Junction to Streatham South Junction | 8 |
| SO682 | Streatham Junction to Streatham Common | 8 |
| SO685 | Streatham North Junction to Streatham South Junction | 8 |
| SO690 | Herne Hill to Tulse Hill | 8 |
| SO700 | Streatham South Junction to Sutton (via Wimbledon) | 8 |
| SO710 | Sydenham to Crystal Palace | 8 |