Amended train timetables brought in during a month of rail strikes will remain in place until Friday, despite the walk out ending on 1 January.
Members of the Rail, Maritime and Transport (RMT) union on South Western Railway (SWR) walked out for 28 days in a dispute over the role of guards.
SWR said the amended timetable would continue for two days to allow guards to refresh their safety procedures.
Further disruption will also continue at the weekend with engineering works.
RMT general secretary Mick Cash paid tribute to the striking workers who "stood firm... in the teeth of a barrage of hostility from the company".
He added: "The union executive will now consider the next steps in this dispute but be in no doubt, the fight for a railway where safety comes before profits goes on."
'Safety critical role'
The dispute over the role of guards started more than two years ago.
On new trains due to start running next year, SWR wants drivers to operate the doors at every stop to save time.
Union members want guards to decide when to close the doors.
An SWR spokesman said: "We want a guard on every train with a safety critical role. But we want to enable guards to spend more time helping people in wheelchairs and with buggies get on and off the train, walking up and down all the carriages and ensuring the safety of passengers, especially at times of need."
He added: "Despite today and tomorrow not being RMT strike dates, we are running an amended timetable to ensure that all those guards who did not work during 28 days of RMT strike action are properly refreshed in terms of all necessary safety activities."
The company runs services between London Waterloo and Portsmouth, Southampton, Bournemouth and Weymouth as well as Reading, Exeter and Bristol. It also operates suburban commuter lines in south-west London, Surrey, Berkshire, and north-east Hampshire.