The car was pushed 500m down the track by the 0546 First Great Western service between Exeter and Paddington. The car driver was killed but no one on board the train was injured.
Emergency crews are hoping to move the train back to the crossing within the hour to allow the 45 passengers to disembark.
British Transport Police have confirmed that one person has died after a train hit a car on a level crossing in Somerset. It happened near Athelney, which is on the line between Taunton and Castle Cary.
There were no reports of any passengers on the train being injured in the crash.
The car is trapped under the front of the train and services are stopped in the area. First Great Western is operating replacement buses between Taunton and Westbury.
There is major disruption on First Great Western services between Westbury and Taunton after a serious crash at a level crossing in Somerset. The 0546 Exeter to Paddington train hit a car just before 6.30 am at the crossing at Athelney between Taunton and Castle Cary.
Transport Police say no one on the train was hurt. For more information on the delays click here
The accident happened at the crossing on Cuts Road in Athelney, Somerset. Stanmoor Road is now closed in both directions. The road may be closed all morning. Trains are not running between Taunton and Castle Carey as a result. First Great Western is organising rail replacement buses.
Disruption on First Great Western between Plymouth and London Paddington due to problem at a level crossing between Taunton and Castle Cary. Services are currently suspended between Taunton and Castle Cary, with First Great Western looking to source replacement road transport.
There is no current estimate for when a normal service will resume.