The West Coast Main Line has been forced to close in Lancashire this afternoon (November 27) due to damage to the overhead electric cables.
Passengers have been stranded on a train between Preston and Lancaster for four hours after it lost power at around 11am.
The West Coast Main Line remains blocked, with all services suspended until further notice.
Network Rail said engineers are currently on site repairing the damaged cables, but Virgin has warned that services might not be running for "several hours".
Virgin is advising people to postpone travelling north of Preston until later this evening, or tomorrow.
A spokesman said: "We advise postponing travel north of Preston until later today or tomorrow, as services won't be running between Preston and Lancaster for several hours.
"This is due to damage to the overhead electric wires between Preston and Lancaster, where all lines are blocked.
"Tickets for travel with us north of Preston today can be used any time tomorrow, November 28."
Len Barwise, 63, from Kendal, has been trapped on a Virgin train between Preston and Lancaster since 11am.
He had been returning from Preston where he had taken his 11-year-old grandson for an appointment at Royal Preston Hospital, when the train came to a stop.
"It's been four hours since the train stopped in the middle of nowhere, somewhere between Preston and Lancaster", said Len.
"It's getting quite stuffy in the train because there's no air con and some people are feeling a bit tetchy.
"Some people asked to open the doors, but they said we couldn't for safety reasons.
"The conditions aren't good. They've handed out chocolate bars and bottles of water, but even the staff don't seem to know how long it will be.
"After being stuck here for two hours, we were told that another train was coming to pick us up.
"They said it was going to pull up next to our train, put some boards between the carriages and we would have to walk over them to board another train to take us back to Preston.
"But for some reason, they've changed the plans and we're still here after fours hours.
"My grandson Jayden is only 11 and he's been to hospital this morning in Preston. And then we were on our way to Lancaster to visit my wife in hospital there, but I don't think we'll be able to see her tonight now."
Virgin is arranging bus replacements to take passengers to their destinations.
It said services are expected to run as normal from tomorrow.
If you've been delayed by 15 minutes or more, hold on to your tickets and claim compensation by visiting northernrailway.co.uk/delayrepay