Rail passengers on some of the busiest routes in the country faced fresh delays on Monday because of a track defect.
South Western Railway (SWR) services to and from London Waterloo were hit by the latest problem - including services between Exeter, Salisbury and the capital.
SWR services were disrupted last week because of signal failures.
The latest problem was at Wimbledon in SW London, and came a day after the new timetable was introduced, with SWR promising new services.
The issue on the track - which is expected to be fixed on Monday night - has resulted in an emergency speed restriction and a reduction in services.
The Exeter St Davids / Salisbury service is currently diverting via Baskingstoke.