An investigation has begun into the breakdown

Travellers on a Virgin service from Plymouth to Edinburgh found themselves stranded when it stopped at Tebay.

The 0713 BST train from Plymouth to Edinburgh should have arrived in Carlisle just before 1400 BST.

But passengers did not get to the city until after 1830 BST.

The train was already slowed because of speed restrictions imposed by Network Rail during the hot weather.

The air conditioning broke down and we were left with almost no air inside the carriages Nicola Jones, passenger Trains delayed by heatwave

Nicola Jones, who was travelling from France to Carlisle, said it was close to being unbearable.

She said: "We were left without any information for over an hour.

"These new trains did not have windows that could open so it was like a greenhouse effect.

"The air conditioning broke down and we were left with almost no air inside the carriages.

'Full investigation'

"We were eventually told that the brakes had failed.

"It was intolerable."

A Virgin spokeswoman said the service, which was made up of two trains linked together, suffered a "technical fault".

Overhead power cables and power on the rails were switched off while Virgin staff and the British Transport Police escorted passengers off the train, and along the West Coast Main Line.

Some passengers left the train and opted to continue their journey by road.

The Virgin spokeswoman added that a full investigation into the incident would be carried out.

Hardest hit

The hot weather speed restrictions brought big delays to other travellers on the busy West Coast route.

Many train companies are running services at a slower than usual speed, amid concern tracks may buckle in temperatures of 30C plus.

Network Rail imposed a limit of 60mph on tracks where trains would normally travel at 110mph.

The head of the Strategic Rail Authority, Richard Bowker, blamed Network Rail's predecessor Railtrack for some of the delays.

He said the former privatised company had allowed areas of track to deteriorate.

The worst-hit UK station has been Birmingham New Street, where half the trains to London were cancelled and Virgin passengers faced average delays of 45 to 60 minutes.