Shropshire Fire & Rescue Service were called about a fire at the Telford Steam Railway in Bridge Road, Horsehay, at 7.18am.
Bosses at the site said the incident involved a piece of electrical equipment that had overheated.
Two fire appliances were mobilised from Telford Central and Wellington Station and an operations officer was also in attendance.
Chris Whitehead, one of the railway's directors, stressed the incident was not going to impact the site's popular festive plans.
Mr Whitehead said: "It won't affect the Polar Express, it was on a different part of the site and wasn't anything serious.
"Fortunately, there were contractors using the site early this morning and spotted the smoke."
The site will be open as usual for the Polar Express experience which begins this Friday and runs until Friday, December 23.