TRAIN users between Eastleigh and Fareham face delays of up to 30 minutes due to a signalling fault.
The fault is between Hedge End and Botley and was discovered at just after 5pm.
Commuters at Fareham, Portchester, Cosham, Hilsea, Fratton, Portsmouth and Southsea, and Portsmouth Harbour stations are affected by the problem.
South West Trains says some trains may be diverted via St Denys.
Passengers travelling to Hedge End or Botley are advised to travel to Fareham and use a train towards London if their train is diverted.