Accident investigators at the scene of Tuesday's crash

Investigations into how the vehicle came off a road at Great Bowden and rolled down the track are continuing.

British Transport Police say they are frustrated that no witnesses to the crash off the A6 have come forward.

More than 100 people were on board the Midland Mainline train, but no-one was seriously hurt. The van driver is being treated for minor injuries.

The vehicle plunged off the A6 Market Harborough bypass on Tuesday morning.

It careered down a bank on to the track and was hit by the 0521 Sheffield to London service, which was travelling slowly as it approached a station. It did not derail.

An accident such as this has never occurred on this route before and it is very, very rare Malcolm Holmes, area station manager

Officers believe the route would have been busy at the time the red Vauxhall Astra van left the carriageway and fell headlong into the path of an oncoming express train.

The driver is still being treated at Kettering Hospital.

Although injured, he managed to scramble free from his vehicle as the train hit.

Malcolm Holmes, area station manager, said: "An accident such as this has never occurred on this route before and it is very, very rare.

"There hasn't been a serious incident on this route for some years which is very good.

"Safety is important to us as an industry and it will continue to be so."

The wreck of the van hit by a Midland Mainline train on Tuesday

Eyewitnesses have described when the train collided with the vehicle as like going over stones in a car, as if something was hitting the underneath of the train before it gradually came to a halt.

They said they did not realise the severity of the situation for some time.

The area was strewn with small pieces of wreckage from the van and work tools were spread over the track.

"With incidents like this we are very quickly on the scene," said Mr Holmes.

"Our priority is to ensure the safety of those people on the train.

"Then our priority is to get the line reopened as quickly as possible and assisting the police and Network Rail with their inquiries.

'Crash debris'

"The line was fully reopened at full speed just after 2pm on Tuesday," Mr Holmes added.

Passengers were transferred from the train, which suffered extensive damage in the impact, on to another train to take them away from the crash scene.

Debris was removed from the line with the first services passing through Market Harborough northbound by lunchtime.