Around 175 passengers have been evacuated from a train which caught fire and "filled up with smoke" near Derby.
Images posted on social media showed smoke billowing from one end of the train as passengers stood at the side of the track.
British Transport Police (BTP) said there were no reports of anyone hurt in the blaze, which took place on a CrossCountry service from Birmingham New Street to Glasgow shortly after 1pm.
One passenger, Matt Navarra, a social media consultant, told the Press Association the carriage had "filled up with smoke fast" after the fire broke out underneath.
Firefighters are dealing with the incident but smoke is currently causing visibility issues, so as a safety precaution we are closing the road. There are likely to be delays so please avoid the area. (2/2)
-- Derbyshire Police (@DerbysPolice) July 18, 2018
Mr Navarra said: "It was looking bad when I left the train and (was) fully ablaze under the carriage. No one was tackling it at that time."
"They evacuated the first two carriages first by placing people in the other carriages but now the police are here and we all got taken off and had to walk along the track," he added.
(BTP) said there was likely to be some disruption to rail services and nearby roads as the fire and surrounded smoke was dealt with.
CrossCountry offered "sincere apologies" for the incident on Twitter.