engineers were last night still trying to work out what caused a Doncaster pit tip to move and engulf a nearby railway line, disrupting train services.
It could be ‘some time’ before the track near Hatfield Stainforth station is repaired and re-opened following the ‘heave’ in the early hours of yesterday.
Management at Hatfield Colliery have called in independent experts to establish the cause of the spoil heap movement.
Record rainfall during 2012 is one theory being investigated.
Train passengers expressed relief that the landslip happened in the middle of the night when there are no services.
Network Rail said the potential problem had first become apparent on Saturday but the situation became much worse at around 3am yesterday when reports of movement were received.
One stretch of track on the south side of the colliery was buckled by the movement and other sections were submerged under spoil for a length of up to 250 yards.
South Yorkshire commuters wanting to travel east beyond Doncaster were forced to use replacement buses yesterday.
As Network Rail teams investigated the scene yesterday morning they were ordered to move off by health and safety officials from the colliery, which is now run by Hargreaves Coal Services.
The firm’s spokesman said it was ‘purely a precaution’ because of the tracks ‘heaving’.
He added: “Obviously we have teams and engineers in attendance and we have also brought in a number of external experts to conduct a detailed assessment.
“At this stage there is no way we can speculate on any causes which is why we have brought in the experts, who are civil engineers, whereas our team are mining engineers.
“At the moment we are dealing with movement of the colliery tip. Once we have a clearer picture of what the causes are, we can decide what to do.”
A Network Rail spokesman said: “We have been carefully monitoring the track near Hatfield Colliery at Stainforth since Saturday afternoon when a train driver reported a ‘rough ride’. Train services in the area have been carefully managed to protect safety.
“Unfortunately conditions have worsened and yesterday morning the colliery advised our staff to vacate the area.
“We anticipate there will be disruption to services between Doncaster and Goole and Doncaster and Scunthorpe for some time.
“Our engineers are working with the colliery to understand the cause of the movement of the spoil heap and to develop a safe plan to manage this and restore the track.
“We apologise to passengers for the inconvenience caused.”
Thorne man Peter Watson, boarding a bus at Doncaster station to get home yesterday, said: “It’s a bit of an inconvenience having to go by bus but there’s nothing else we can do. I hope it doesn’t take too long to repair the track.
“I suppose it’s fortunate it happened at night otherwise there might have been a serious accident.”
Buses replaced Northern Rail and TransPennine Express trains between Doncaster and Goole/Scunthorpe, with journey times extended by up to 60 minutes.
Services between Sheffield and Bridlington/Scarborough were being diverted via Selby, and did not call at Goole, and services between Doncaster and Scunthorpe are suspended.
First TransPennine Express services between Manchester Airport and Cleethorpes were not running between Doncaster and Scunthorpe.
A spokesman for Northern Rail said: “Emergency engineering works are being carried out at Hatfield Stainforth due to a landslip. We apologise for any inconvenience caused.”