Network Rail has suspended a major steam train operator over safety fears after an engine and 13 carriages failed to stop at a signal.
West Coast Railways runs services on the famous Settle-Carlisle route and runs successful scenic trips in the Scottish Highlands, as well as other routes.
It was running the steam locomotive Tangmere, plus coaches, from Bristol to Southend last month when a Spad (signal passed at danger) incident happened at Wootton Bassett junction.
No-one was injured and the service did not derail but Network Rail said in a letter to the company that it was the most serious Spad this year.
Following an investigation, Network Rail has issued the operator with a set of safety concerns that the firm which is based in Carnforth, Lancashire, must address.
In the meantime it is suspended from operating on the rail network.
A spokesman said: "Network Rail has issued a suspension notice to West Coast Railway Company Limited (WCR) as a result of ongoing safety concerns.
"This decision has not been taken lightly; however safety will always be our number one priority.
"We have set out a number of actions to address the safety concerns raised and will continue to work with WCR to ensure their services can run safely in future."
West Coast Railways assured customers that it was trying to get the suspension lifted.
On its Facebook page, it said: "West Coast Railways are working hard to reverse the current suspension imposed by Network Rail by fully satisfying their concerns.
"Passengers booked to travel with West Coast Railways and on their associated trips should not be concerned. If necessary, West Coast Railways will charter the service of another licensed operator using the same traditional carriages and trips will be unaffected, but West Coast Railways hope this won't be necessary and trust any issues will be resolved to the satisfaction of Network Rail."