British Transport Police say they are investigating an incident at a level crossing near Datchet in which a car was involved in a collision with an empty train at around 6am.
The train was not in service at the time and it's understood that there were no injuries to the driver or guard on board.
Trains are not currently running between Windsor & Eton Riverside and Staines and replacement road transport is in operation for passengers.
Customers can also use First Great Western services on any reasonable routes. This is expected to continue for most of the morning.