Passengers were forced to contend with temperatures of up to 40 degrees when a train became stuck between Lowestoft and Oulton Broad North.

The train, an old Class 37 unit, had no windows which could be opened by passengers, and was unable to move forward to the next station due to a signal and points failure.

Eyewitnesses on the train described children on the verge of 'heatstroke', abuse being shouted at employees, and one man who said he was a diabetic threatening to call the ambulance service.

The delay saw the train sit in the baking sun for almost an hour and a half before the train returned to Lowestoft station.

One passenger said: 'One man shouted out that is was 39 degrees on the train, and there were kids who were really dehydrated.

'They were in swimsuits and looked like they'd been to the beach and been running around all day. It was awful.

'The staff were wonderful though, and were handing out bottles of water. There was nothing they could really do.'

The train, the 3.48pm Lowestoft to Norwich service, did leave Lowestoft nearly two hours later, at 5.45pm.

During the 45 minute journey to Norwich water was again handed out by the conductor.

A Greater Anglia spokesperson said: 'We apologise to passengers for the delays on Monday, this was due to a points failure near Lowestoft.

'The conductor on the train did everything possible to make passengers comfortable in the heat, including walking through the train several times, handing out bottled water, keeping them updated and helping them.

'He also re-stocked the train with more bottles of water when it arrived in Lowestoft.'

She added: 'At the moment there is a nationwide shortage of diesel trains, so whereas in the past we've been able to hire one from elsewhere if one of ours becomes damaged or develops a fault, it's a lot more difficult to replace them now.

'We currently lease the Class 37 trains and are unable to make any modifications, however we will discuss this further with our supplier.

'From next year we're replacing all of our trains with brand new trains which will all have air conditioning, and other features to make our customers' journeys more comfortable.'