Train services on the Uckfield Line return to normal from today (November 30).
There has been a month of disruption caused by work on extending platforms between Uckfield and Hurst Green to accommodate longer trains.
During the last four weeks, day-time services have been suspended with the last train out of town at 08:31 and the first back, the 16:08 service from London Bridge.
There will be further disruption in the new year.
Services between Uckfield and Crowborough will be totally suspended between Janaury 4 and February 20 and will be replaced by buses from Uckfield and Buxted to Crowborough to connect with services.
From February 29 to March 24, the off-peak closure between Uckfield and Hurst Green will resume.
During this whole period, there maybe weekend and overnight closures.
Train operator Southern said: “This staggered approach to the project means it will only affect areas when and where the specific works are taking place.
“It means the project will be delivered as soon as practically possible, with the least amount of people disrupted, compared to other closure options that were reviewed.
“Under this plan Network Rail will also be able to undertake significant drainage works required in Crowborough Tunnel which would not be possible in any other option considered.
“These must be done and would require significant lengthy line closures in one – two years’ time if not undertaken during these works.”
The platform extensions at eight stations will allow ten-coach trains to operate on the route, which is often over-crowded in the morning and evening peak periods.