PICTURES have been released of the huge mound of ice that caused the near-disastrous derailment of a York train.

Investigators say the block of ice on the tracks was 26ft long – almost the third of the length of a carriage.

The ice had built up in a ventilation shaft in a tunnel before falling on to the tracks, according to the Rail Accident Investigation Branch (RAIB). The organisation is now carrying out a wider review of how Network Rail deals with ice in tunnels.

The 00.38 TransPennine Express from Manchester Airport to York was travelling at 70mph when it hit the ice but it remained upright, bouncing along the tunnel wall before coming to a stop. Firefighters said afterwards that had it derailed to the right instead of the left, the train could have gone on to its side, injuring or killing those on board.

More ice fell on to the train after it had stopped, as panic-stricken passengers waited to be freed. All 45 passengers and the crew had to be evacuated from the three-carriage train after the accident in Summit Tunnel, Calderdale, at 1.19am on December 28.

A spokesman for the RAIB said the block of ice was measured after the accident and was two metres high and eight metres long (about six and a half feet by 26 feet).

He said preliminary examinations showed the ice had fallen from the ventilation shaft, linking the tunnel with the moorland above.

He said: “There was evidence of an extensive build-up of ice on the walls of this shaft. There was also significant ice debris underneath the adjacent shaft.

“He said that immediately after the derailment, more ice fell on to the train roof of the train “causing alarm to the occupants”.

It was nearly three and a half hours before everyone was evacuated from the train and led out of the tunnel to the emergency services. Nobody was injured but the train suffered damage, including to the cab windscreen.

The spokesman said the RAIB was aware of “a number of incidents” involving ice in tunnels during the past two winters and subsequent thaws, and said: “The RAIB’s investigation will include a review of Network Rail’s arrangements for the identification of ice-related hazards in tunnels and the steps taken to mitigate the consequent risk.”

Speaking to The press previously, passenger Brenda Duthoit, 62, said: “The whole incident was quite traumatic and could have been a major disaster had the train rolled over on to the track instead of hitting the wall.

“I held on to the seat in front and thought the train was going to roll over, then there was a horrible grating noise which was presumably the train hitting the side of the tunnel.”