Coal shortage hits Vintage Trains and Severn Valley Railway
A heritage steam train service could be under threat unless its operator can find a reliable source of coal.
Vintage Trains Ltd, based in Tyseley, Birmingham, said it had just enough supplies to last until the end of June.
The firm had bought fuel from Daw Mill colliery in Warwickshire, until its closure after a fire in February.
Vintage Trains said the move, coupled with the collapse of Scottish Coal last month, had caused a run on steam coal.
There about 200 heritage rail companies in the UK, many of them operating steam trains.
Managing director of Vintage Trains Bob Meanley said locomotives needed a specific type of coal that was difficult to find.
"We're concerned and seriously worried. There are supplies of foreign coal getting into the country, but indigenous supplies are very hard to get hold of," he said.
UK Coal said it still produced steam grade fuel at its mine in Kellingley, Yorkshire, but that the "unavoidable" closure of Daw Mill had had an impact on its overall production.
Last year the colliery produced about two million tonnes of coal, about 95% of which went to power stations.
House coal and that used by power stations is often unsuitable for locomotives, which require large-grade fuel with a very high burning temperature.
Scottish Coal produced the fuel used by the Severn Valley Railway, which carries about 250,000 passengers a year between Bridgnorth in Shropshire and Kidderminster in Worcestershire.
General manager Nick Ralls said the heritage line had secured supplies of Russian coal.
He said: "You think coal is coal, but no, it's got to have the right burning properties. If it hasn't, you get it clinkering up in the firebox, causing problems for the fireman."
Mr Meanley said using Russian coal would mean an increase in price of 10 to 12%.
Without a reliable source, he said, the firm may be forced to turn to diesel engines - a decision likely to be unpopular with the line's passengers.