I am extremely disappointed that the ASLEF and the RMT unions have called further strike action.
ASLEF strike action will take place on Friday 12 May, Wednesday 31 May and Saturday 3 June. On these days there will be no Southern, Gatwick Express or Thameslink trains operating for the whole day.
ASLEF have also advised their members not to work non-contractual overtime on Saturday 13 May, from Monday 15 to Saturday 20 May inclusive and on Thursday 1 June. On these dates there will be an amended service with fewer trains.
RMT members will take strike action on Saturday 13 May. Services will start later and finish earlier than normal. Two trains per hour will serve Billingshurst, Christ's Hospital, Horsham, Littlehaven, Faygate (limited services) and Balcombe in either direction.
GTR strongly advises that you plan your journey beforehand: https://www.nationalrail.co.uk/
Further information on the industrial action, including ticket exchanges and refunds, can be found here: https://www.thameslinkrailway.com/travel-information/plan-your-journey/industrial-action
Please see the below file for GTR’s diagram of services running on Saturday 13 May.