Railtrack has identified 81 trouble spots where engineers fear trains could be derailed by tracks that have started to break up.

A broken rail is suspected of causing the Hatfield disaster in which four people died and 35 were injured.

Speed restrictions have been imposed around the trouble spots while a safety review is carried out and this is likely to cause delays in passengers' journeys.

Locations are listed below with the "precautionary" speed restrictions now in place in brackets.

Southern

Dunton Green (60mph), Coulsden North-Quarry Tunnel (20mph), Spa Road (40mph), Earlsfield (40mph), Three Bridges - Balcombe Tunnel (60mph), South Croydon (20mph), Wimbledon (50mph), Wimbledon West Junction (50mph), Wimbledon West Junction (20mph), Earlswood (60mph), Earlswood (50mph), Earlsfield (40mph), Wimbledon (20mph), Chelsfield (55mph), Knockholt (55mph), Polhill (Twiton) (55mph), Eynsford (Lullingstone) (40/50mph), Eynsford, (40/50mph).

Great Western

Clink Road & Fairwood Junction (30/70mph), Tiverton Loops & Hele & Bradninch (70mph), Hele & Bradninch LC & Tiverton Loops (70mph), Hyde Farm Crossing & Cogload Junction (70mph), Cogload & Hyde Farm Crossing (70mph), Didcot East (20mph), Blatchbridge Junction & Clink Road Junction (70mph), Gwyn-y-Gaer LC & St Georges HABD (50mph), Pewsey & Savernake (40/60mph), Thatchem CCTV (20mph).

East Anglia

Lakenham (60mph), Ingatestone (60mph), Chelmsford (20mph), Seven Kings to Ipswich (20mph), Colchester (20mph), Seven Kings to Ipswich (20mph), Shenfield-Ipswich (70mph), Witham (20mph), Elsenham & Newport (50mph), Hackney Downs & Bethnal Green (30mph), Hackney Downs & Bethnal Green (30mph), Tottenham Hale (40mph), White Hart Lane (30mph), Liverpool St-Shenfield (50mph).

London North East

Aycliffe (50/75mph), Preston Manor (50/75mph), Bradbury (50/70), Aycliffe (50/75mph), Preston Manor (50/75mph), Ferryhill (20mph), Durham (20mph), Newton Hall (20mph), Marshall Meadow (20mph), St Neots (50/80mph), Offord (50/80mph), Fletton (50/70mph), Helpston (50/80mph), Hettmill (20mph), Egmanton (50/80mph).

Midlands

Leighton Buzzard (20mph), Rugeley South (20mph), Atherstone (20mph), Norton Bridge (20mph), Lichfield/Hademore (20mph), Shambrook (20mph), West Hampstead (20mph), Heyford (20mph), Irchister (20mph), Market Harborough (20mph), Kettering (60mph), Market Harborough (40mph), Watkins LC & Kirby Bridge Junction (60mph).

North West

Brent Curve Hendon (20mph), Southwaite (20mph), Eden Valley & Penrith South Junction (50/70mph), Tebay North Junction & Shap Summit (50/70mph).

Scotland

Harrisons Sidings GF & Shap Summit (50/70mph), Rutherglen & Newton West Junction (20mph), Law Junction & Shieldmuir (20mph), Lanark Junction & Carluke (20mph), Carluke & Law Junction (40/60mph), Law Junction & Shieldmuir (30/50mph), Carstairs & Lanark (20mph), Cove LC & Kirtlebridge (40/60mph).