Five people were hurt when the Flying Scotsman was involved in a 'slow speed' crash with another heritage train hours before visitors were due to board.
The crash happened at Aviemore Railway Station, in the Cairngorms, Scottish Highlands, at 7.10pm on Friday.
The station is home to Strathspey Railway, a heritage line which takes visitors on steam trains in northern Scotland.
Two people were taken to hospital as a precaution but their injuries were not believed to be serious, police said.
A spokesman for the National Railway Museum, which owns the Flying Scotsman, said: "We can confirm that steam locomotive Flying Scotsman has been involved in a shunting incident at Aviemore Station.
"We will provide further information once more details are known."
Scottish Fire and Rescue Service (SFRS) sent eight appliances to the scene, and Police Scotland said other casualties were treated at the station.
A spokesman for SFRS said: "We were alerted at 7.10pm on Friday to reports of a collision involving two trains at Aviemore Railway Station.
"We sent eight appliances to the scene, where firefighters worked to support partners.
"Three appliances remain at the scene.
"Two casualties have been transported to Raigmore Hospital.
"Three casualties were treated at the scene but did not require to be taken to hospital."
A Police Scotland spokesperson said: "Around 7pm on Friday September 29, we received a report of two trains colliding at low speed at Aviemore Railway Station.
"As a precaution, two people - a man and a woman - were taken to Raigmore Hospital in Inverness by the Scottish Ambulance Service for treatment. Their injuries are not believed to be serious.
"A number of other passengers were assessed by the ambulance service at the scene and did not require hospital treatment.
"Inquiries are ongoing to establish the full circumstances."
During 2023, as well as days out on the mainline, Flying Scotsman can be seen at free static events at the National Railway Museum and other locations. The iconic loco will also be in action at a number of heritage railways around the UK and at Locomotion in Shildon.
Flying Scotsman was scheduled to be running trips this weekend, with the line expected to be especially busy.
A spokesman for Network Rail said: "It's on a heritage railway line, it's not our infrastructure.
"The main line is shut while emergency services respond.
"We are saying to passengers to check before travelling."
A statement from the Belmond and Strathspey Railway said: "We can confirm that on Friday September 29 at 1815, a shunting incident occurred when the Flying Scotsman locomotive was being coupled with Belmond's Royal Scotsman train carriages, which were stationary on heritage railway line, Strathspey Railway.
"Flying Scotsman was visiting the railway as part of a planned excursion.
"Emergency services attended the site to provide assistance. Two people attended hospital and were later released, with others being treated at the scene.
"Appropriate authorities were notified immediately, and we are co-operating with their investigations."
A tourist booked to travel on the world-famous steam train on Sunday saw the aftermath of the crash.
Lewis Smith travelled up from Glasgow and was surprised to see emergency services outside the station.
He said: "We arrived here quite late and so we took a walk into Aviemore to get something to eat.
"We passed by the station and saw the Flying Scotsman and a fire engine at the platform.
"We decided to come back to see what was happening after getting food. At around 8.30pm we came back to the station and got some photos of the engine.
"There didn't seem to be anything wrong apart from all signals on the mainline being set to red but I didn't really take much notice.
"When we got back we got a phone call from a friend asking if we had seen the accident. We didn't know anything was wrong until we checked the news."
Flying Scotsman is making tours around the country as part of its centenary celebrations.