Last update 22 December 2020
Additional information is always gratefully received, whether entirely new records (particularly historical records), or information to fill in gaps or correct errors, via the contact link under the Miscellaneous entry in the navigation bar above. Thank you.
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) | Note 1 |
| 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 | Note 8 |
| 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 Subsumed 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) | Note 2 |
| 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 | Note 5 |
| 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 See also note 6 |
? |
| SO410A | Regents Canal Junction to York Way North Junction See also note 6 |
? |
| SO410B | Regents Canal Junction to Cedar Junction See also note 6 |
? |
| SO420 | Ripple Lane CTRL connecting lines See also note 6 |
? |
| SO420 | York Way South Junction to Camden Road Incline Junction See also note 6 |
? |
| SO430 | Ebbsfleet to Springhead Junction See also note 6 |
? |
| SO430 | Stratford International West Junction to Temple Mills International Depot See also note 6 |
? |
| 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) | Note 7 |
| SO520A | Ford Junction to Littlehampton Junction | 8 |
| SO530 | South Croydon Junction to East Grinstead | Note 3 |
| SO540 | Hurst Green Junction to Uckfield | Note 9 |
| 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 | Note 4 |
| 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 |