Brighton commuters are facing delays of up to an hour this morning because of emergency engineering works at Haywards Heath.
A broken rail was reported at about 8am. UPDATE – Work to repair the rail was completed at about 11.40am – almost two hours after the initial estimate.
Network Rail said that there would be knock-on delays and disruption for some time.
Train operator Southern said: “Owing to emergency engineering works at Haywards Heath services are now able to operate south from Haywards Heath but at a reduced speed.
“Services are subject to short notice alterations, cancellations and delays of up to 60 minutes.
“Buses are supplementing the train service between Haywards Heath and Brighton.”
Thameslink said that its services could be subject to short notice alterations and added that replacement buses were in use.
The unofficial Brighton Station account tweeted: “Major issues HHE tunnel. Service now going to be ruined. CODE RED.”