ScotRail said the train was towed by a diesel locomotive to Preston

Vandalism has not been ruled out as the cause of massive delays to rail passengers on the West Coast Main Line.

Network Rail said investigations were continuing into why overhead cables came down on the busy route which links London to Scotland via Cumbria and Lancashire.

Rail passengers will experience delays and cancellations throughout the weekend, rail operator ScotRail confirmed.

Almost 200 passengers were stuck on an overnight sleeper service from Inverness to London after the power lines collapsed at Oubeck, around five miles south of Lancaster at 0430 BST on Friday.

ScotRail said the problem led to the cancellation of Friday night's sleeper services from Glasgow and Edinburgh to London, and those heading north from London.

ScotRail managing director Peter Cotton apologised to passengers and promised them full refunds for unused tickets.

He said: "We are extremely sorry to have taken the decision.

Resumed services

"Although our contingency plans got passengers from Friday morning's incident to London by lunchtime, the train itself arrived too late for servicing and repair at Wembley Depot.

"In addition, our on-board staff would not have had sufficient recovery time before being asked to make the return trip."

ScotRail said services will resume on Sunday, as the trains do not run on a Saturday.

But it confirmed bookings would be cancelled for Sunday and Monday as a "precautionary measure".

Connecting buses were provided for passengers who had planned to travel south on the sleeper on Friday, while a fleet of luxury express coaches replacing the northbound sleeper service.

The sleeper became stuck for more than three hours while the cables were cleared from the track.

The 170 passengers on the train, which was scheduled to reach London at 0652 BST, arrived early Friday afternoon.

A Network Rail spokesman said one line was reopened this afternoon and added: "We hope to get the repairs up and running by sometime on Saturday.

"We have not ruled out the fact that vandalism may have been the cause."

Virgin Trains said its services south of Lancaster would be disrupted until Saturday by up to 90 minutes.