A derailment at Grange-over-Sands in Cumbria is set to block the line for another two weeks, Network Rail has warned.
The accident happened early on 22 March. No one was hurt, but a derailed Northern unit has damaged the track.
Engineers have been investigating conditions at the scene, because a void in the ground was found about 150m from the derailment.
The Rail Accident Investigation Branch has also been gathering evidence.
Work to clear the line will involve using a crane to lift the train and then repairing the ground and the line. Some new track will be necessary.
Network Rail’s North West route infrastructure director Chris Pye said: ‘On the rare occasions trains leave tracks like this it can cause extensive damage and unfortunately this incident is no exception. The additional problem with the ground conditions means this is an especially complicated recovery process.’
Services over Easter were already set to be affected by other engineering work which was not connected with the derailment.
Trains are running from today between Carlisle and Barrow-in-Furness, while buses are replacing trains between Barrow and Lancaster.