RAIL passengers are being warned that an overtime ban by train drivers on Southern will hit up to a quarter of services.

Members of Aslef will stop working overtime from today in a long-running dispute over driver-only trains.

The union is also holding a ballot for strikes in a separate row over pay.

Southern said it plans to operate 75 per cent of its weekday services on June 29 and 30 and is working to improve on this number from July 3.

“This will create a timetable with stability and consistency. Passengers are advised to expect a reduced service on certain routes and to allow extra time for their journeys,” said a statement.

Passenger services director Angie Doll said: “This action is going to be very inconvenient to our passengers and communities, but by putting in this revised timetable, we will be able to run a more reliable and consistent service. We urge Aslef to put an end to their industrial action and allow passengers to get on with their lives.”

In summary:

Thursday and Friday, June 29 and 30: Most routes will retain a Southern train service, including Seaford. On other routes, ticket acceptance has been arranged with other operators.

Key alterations include:

• No off-peak Gatwick Express service between Gatwick Airport and Brighton (but a limited peak service will operate)

• Gatwick Express services will operate to an amended timetable between London Victoria and Gatwick Airport

• No Southern service to/from Beckenham Junction

• No service between East Croydon and Milton Keynes Central via Kensington Olympia (a limited peak service will operate between Clapham Junction and Watford Junction)

• No direct service between London and either Portsmouth or Southampton (a change of trains will be required)

• Very limited peak services between Tulse Hill, Peckham Rye and London Bridge

• No Southern peak-only service to/from Guildford

• No Southern peak-only service to/from Wimbledon

• An hourly service will operate between Seaford and Brighton

• A reduced peak service between Ashford International and Hastings

Weekends, from 1 July:

Southern will run its normal timetable but services will be reduced and the number will vary weekend to weekend. For information about these services, visit southernrailway.com/dispute.

Mondays to Fridays from Monday 3 July until further notice:

Most routes will retain a Southern train service and significantly more services will be running from Monday 3 July than on Thursday 29 and Friday 30 June.

The key alterations are:

Most services on the following routes will be restored:

• Gatwick Express services between London Victoria and Brighton - the full Gatwick Express service will operate

• West London Line services between East Croydon and Milton Keynes Central via Kensington Olympia and Watford Junction

• Brighton to Seaford services will operate every 30 minutes

• Direct services between London and Portsmouth / Southampton

• Peak-only services between London Bridge and Guildford

The following services will not operate:

• Ashford to Rye / Hastings peak-hour additional services (*)

• Brighton to Lewes shuttle services (*)

• Brighton to Hove shuttle services (*)

• London Bridge to London Victoria via Crystal Palace (*)

• London Victoria to Epsom via Mitcham Junction (*)

• London Bridge to Beckenham Junction via Crystal Palace

• Off peak London Victoria to Reigate and Tonbridge services will be replaced by a Tonbridge to Reigate (via Redhill) service (*)

• Off peak fast services between Redhill and London will not operate (*)

• On other routes, a limited number of services will also not run.

(*) On these routes, alternative Southern services will be available, but the overall frequency of service will be reduced and passengers may have to make a change of trains to complete their journey.

On routes with a reduced or withdrawn service, passengers are advised to travel at less busy times if possible and to allow extra time for their journey, especially where it involves using another operator.