From the FGW website :

10:04 Reading to Redhill due 11:24
This train has been cancelled.This is due to signalling problems.


10:34 Reading to Gatwick Airport due 11:50
This train will be terminated at Guildford.It will additionally call at: Crowthorne, Sandhurst, Farnborough North, Ash and Wanborough.It will no longer call at: Dorking Deepdene, Reigate, Redhill and Gatwick Airport.This is due to signalling problems.


10:34 Redhill to Reading due 11:53
This train will be terminated at Guildford.It will no longer call at: Ash, North Camp, Farnborough North, Blackwater, Sandhurst, Crowthorne, Wokingham and Reading.This is due to signalling problems.


11:03 Gatwick Airport to Reading due 12:19
This train has been cancelled.This is due to signalling problems.


11:34 Redhill to Reading due 12:53
This train has been cancelled.This is due to signalling problems.

Line problem between Reading and Gatwick Airport.
Train services between Reading and Gatwick Airport via Guildford are being disrupted due to signalling problems.Engineers are working as fast as possible to restore services to normal. Short notice alterations, cancellations and delays can be expected.

There will be an hourly train service between Reading and Guildford, and an hourly train service between Guildford and Redhill. Tickets will continue to be accepted on the Tube, Gatwick Express & South West Trains.