A station has reopened after it was evacuated when thick smoke was seen billowing from a train.

The fire service was called to Queen Street station in Glasgow at around 7.40am on Tuesday after the alarm was raised.

Pictures posted on social media showed smoke billowing across the station as passengers made their way outside.

It is thought the smoke was caused by excessive fumes belching from one of the trains.

Train services resumed after the fire alarm was reset but ScotRail warned that there may still be some disruption to services.

ScotRail tweeted: “The disruption was caused when one of our trains experienced an engine fault as it prepared to leave Queen Street.

“The fault resulted in smoke coming from the engine, which set off the fire alarm at Queen Street. While there was smoke, at no point was there a fire.

“There were no customers on the train at the time. At no point was safety compromised, either on the train or at the station.

“The train has now returned to the depot for further examination.”

The fire service said it was a false alarm with good intent.

A ScotRail spokeswoman said: “We are sorry to customers for the delay to their journey and will do everything we can to get services moving as quickly as possible.”

Transport workers’ union RMT voiced concerns about the incident.

General-secretary Mick Cash said: “RMT would like to thank our colleagues from the Scottish Fire and Rescue Service for their prompt response to the incident this morning.

“However, it raises serious questions about the current state of Scotland’s railways when we are being told that we have the ‘best railway Scotland has ever had’. That claim is clearly nonsense.

“This morning we had a vintage HST train pouring out thick black smoke forcing the closure of one of Scotland’s busiest train stations.

“We are supposed to be spending millions of pounds on investment in our railway – yet we end up using clapped out, decommissioned intercity trains that are 50 years old and that are in no way environmentally friendly or fit for purpose.

“Scotland’s railways are nothing more than a shambles under the current privatised and fragmented system.”