Rail passengers suffered travel chaos on Sunday because of a signalling problem on busy routes.
South Western Railway urged people not to attempt to travel between Brockenhurst and Eastleigh or between Fareham and Southampton as lines were blocked.
A message to passengers said: “We are currently unable to operate a service between Brockenhurst and Eastleigh in both directions.
“We are also currently unable to operate a service between Fareham and Southampton Central.
“Train services running through these stations may be cancelled, delayed or revised. Disruption is expected until the end of the day.”