Some passengers on the West Coast Mainline have been stranded for hours as an electric overhead cable snapped.
The cable broke on the route between Lancaster and Preston at about 08:35 GMT blocking both lines in both directions, Network Rail said.
One passenger tweeted they had been on a train for seven-and-a-half hours, while another called it “an absolute horror show”.
Virgin Trains said the disruption would continue until Thursday.
It is not yet known what caused the cable to snap.
Northern and Trans Pennine Express services in the area have also been affected.
Passengers expecting to use the route have been advised not to travel, and have been warned journey times would be at least three hours longer than usual.
Virgin train tickets could be used on Thursday, the rail services said.