A motorist was killed when an 80mph train ploughed into her car at an unmanned level crossing.

Passengers told of their shock as they were confronted with the gruesome sight of the woman's dead body as their train ground to a halt after dragging the Mini more than 100 yards.

Although 18 passengers and the driver were uninjured, emergency workers said the incident could easily have led to a major disaster if the train had derailed.

Union leaders yesterday called for a review of safety at level crossings throughout the network.

Police are investigating whether the woman deliberately parked in the train's path in a suicide bid.

The 10.53am Southern service was half an hour into its journey from Brighton to Ore, near Hastings, when the driver first saw danger ahead.

Passengers told how the three-carriage train slammed on its brakes as it approached a half-barrier crossing at Wilmington, near Polegate.

But it could not stop and hit the blue convertible Mini Cooper, dragging it 100 yards along the track, killing her instantly.

Frederick and Ellen Bennett, both retired, were on board the train heading for a day trip to Eastbourne from their home in Durrington.

Mr Bennett, 81, said: "We heard the screeching of brakes, two bangs and then the train came to a slow stop.

"I looked out the window and I saw the car. I also saw a young woman inside it with her body hunched over the steering wheel, clearly dead. She had long dark hair and looked fairly young. We just sat there on the train, waiting while the emergency services turned up."

Support worker Geraldine Bird, 45, who lives in Polegate, said: "I was a bit shocked by it all. The train slowed down and I remember hearing a bang.

"Afterwards we were all moved to the back of the train and waited until arrangements were made to take us off."

An Eastbourne-based ambulance crew was sent to the scene, along with a paramedic officer, a helicopter and 15 firefighters.

Clinical team leader Guy Emery, of Sussex Ambulance, said: "This incident could have been far worse if the train had been seriously damaged or derailed."

The incident has renewed fears over safety at level crossings, which were the site of 13 deaths last year.

A spokeswoman for the Rail Safety and Standards Board said: "Often accidents at level crossings happen because somebody has misused them."

Hayley Owen, 23, was electrocuted at a level crossing near Chichester in December, 2004.

An inquest heard she was walking home from a night out when she fell on to a live rail in dimly-lit conditions.

Train drivers' union Aslef last night called for a track-to-train system that alerts the driver to obstructions on the track ahead.

General secretary Keith Norman said: "The CCTV system isn't Star Wars it was actually developed in South Wales and has been operating in Hong Kong for eight years.

"We think accidents at level crossings are a major problem. Crossings are inherently unsafe. Accidents are also completely traumatic."

Rail services were severely disrupted by the incident.

Coaches ferried passengers to the nearest train station.

Late yesterday afternoon, services along the Sussex coast continued to be affected but they were running again by evening rush hour.

The train driver will now be tested for alcohol as part of routine procedure although there was no suggestion he was to blame for the crash.

A spokesman for British Transport Police said: "The death is not being treated as suspicious. There were several witnesses, inquiries are continuing and suicide is being looked at as a possibility."

The body was removed from the scene at 2.30pm.