UPDATE AT 5.45PM … Trains are running again although passengers may face delays and cancellations for the next hour or so.
Rail services into and out of Brighton station have been disrupted by a broken down train blocking the track in Haywards Heath.
Several services have already been cancelled, with Southern, Thameslink and Network Rail warning of more delays and disruption.
A “rescue” train has been sent to move the broken down train from a key “set of points” and rail replacement buses have been requested.
The National Rail Enquiries website said: “A train has failed outside of Haywards Heath and is unable to move.
“This has happened over the set of points that would allow trains to divert their destination, namely Brighton or Lewes.
“This means that services between these stations are currently unable to proceed.
“A ‘rescue’ train has been identified to assist the broken down train and is currently headed to the faulty train.”
The website also said: “A broken down train at Haywards Heath is causing disruption to trains between Haywards Heath and Brighton / Lewes.
“As a result of this, trains may be cancelled or delayed. This is expected to continue until 7pm.
“Rail replacement buses have been requested to assist, and we will update you when we have these confirmed.
“All Thameslink services will be terminating and restarting at Three Bridges or Gatwick.
“Southern services between London Victoria and Brighton will be cancelled until further notice.
“London Victoria to Littlehampton will run via a diverted route. Journey times will be extended or terminated at Three Bridges or Haywards Heath.
“London Victoria to Ore / Eastbourne will run only between Eastbourne and Hastings.
“Gatwick Express services will run to and from Haywards Heath only.”
The website also said that train operators would accept each other’s tickets and Brighton and Hove Buses and Metrobus would also accept tickets as appropriate.