The work will affect trains on Monday (January 20) to Friday (January 24).
Work will also affect trains in the Epsom and Dorking area.
We have compiled all the details on these works so that you can plan your journey this week.
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Monday to Friday (January 20 to January 24)
Engineering work is taking place overnight between Purley and Horley, closing some lines.
Between 11.45pm and 5am each night, trains will be diverted between Purley and Gatwick Airport and will not call at stations via Redhill.
Replacement buses will run between East Croydon, Purley, Horley and Gatwick Airport via Redhill.
Engineering work is taking place between Sydenham and Norwood Junction and West Croydon, closing all lines overnight from Monday evening until Friday morning.
As a result:
The 12.17am train from London Bridge to Caterham service will be diverted between London Bridge and East Croydon, not calling at Norwood Junction and running later than usual with extended journey times.
A replacement bus will run from Norwood Junction at 00:30 to East Croydon.
The 12.35am train from London Bridge to East Croydon service will be diverted between London Bridge and East Croydon, not calling at stations via Sydenham, and running later than usual with extended journey times.
A replacement bus will run from London Bridge at 12.35am to East Croydon, calling at all stations via Sydenham.
Passengers should remember that these trains operate very early on Tuesday to Friday mornings but are part of the end-of-the-day service from Monday to Thursday.
Monday to Thursday (January 20 to January 23):
Engineering work occurs between Epsom and Dorking, closing all lines overnight from Monday evening until Friday morning.
From approximately 10pm each night until the end of service, buses will replace trains between Epsom, Dorking, and Horsham.
