Rail services have been disrupted after a train hit a concrete slab near Ifield in West Sussex.
It is believed the slab of concrete was deliberately placed on the line and British Transport Police are investigating after the train was damaged in the incident.
Services between Three Bridges, Horsham and Barnham are being disrupted.
Replacement buses are in operation between:
- Three Bridges and Horsham serving the normal replacement bus stops at Crawley, Ifield, Faygate and Ifield.
- Horsham and Barnham serving the normal replacement bus stops at Christs Hospital, Billingshurst, Pulborough, Amberley, Arundel and Ford.
Metrobus are accepting rail ticket holders on route 23 between Crawley and Horsham and on routes 100 and 400 between Three Bridges and Redhill via Horley, Salfords and Earlswood.
Southern ticket holders may also travel by First Capital Connect between Three Bridges and London and on London Underground between London Bridge and London Victoria.
Southern ticket holders are also being accepted for travel by South West Trains between Havant and Waterloo via Guildford and by First Great Western between Reading and Guildford via Dorking.
Rail engineers said the fault would take at least until 5pm to repair and Southern Rail services have been diverted.
A Network Rail spokesman said: “Services on the line through Ifield are being disrupted after a train struck an object on the level crossing at Bewbush.
“The British Transport Police have been informed and are investigating how the object came to be on the crossing.
“The train was damaged in the incident, as was the infrastructure, and we estimate it will take until at least 5pm to get the train on the move and the lineside equipment fixed.
A Southern Rail spokesman said: “The train is the 12.56 Bognor Regis to Victoria service and it suffered shoe gear damage, the shoes that pick up power from the third rail, while passing though the crossing at approximately 2pm.
“The London bound line is closed at the moment while the train gets rescued, but the southbound line remains open."
A British Transport Police (BTP) spokeswoman said: “Officers were called to Bewbush foot crossing, Crawley, on Friday, 4 April after reports that a train had struck an object on the track.
“Officers from BTP attended the incident, which was reported at 2.42pm.
“The investigation is in the early stages but it would appear that a concrete slab was deliberately placed onto the track, causing damage to the train.
“Fortunately, no one was injured during the incident.”
The spokeswoman added: “Deliberately putting objects onto the railway infrastructure may seem like fun to those who commit such offences but what they don’t realise are the potentially serious consequences of their extremely foolish behaviour.
“Trains travelling at high speeds risk being damaged or derailed, putting passengers’ and rail staff’s lives in danger.
“Police treat incidents where the line has been obstructed extremely seriously."
“If you were in the area at the time and saw anyone acting suspiciously, or know anything about the incident, then please get in touch.”
Anyone with information about the incident should call British Transport Police on 0800 40 50 40, or text 61016, quoting 297 of 04/04/14.