From www.wdwinfo.com

Fire at Seven Dwarfs Mine Train at Magic Kingdom
Nov 1, 2014

Reports began surfacing on social media tonight around 10:20pm EST that the Seven Dwarfs Mine Train at Walt Disney World was on fire. The Reedy Creek Fire Department responded to the fire and no injuries have been reported. It is believed that the blaze may have been caused by windy conditions during the nightly fireworks show. A similar incident happened back in February with the Journey of the Little Mermaid attraction, which is located right next to the Mine Train. The attraction opened in May in the New Fantasyland section of the park.

More specific details are not known at this time.

A video of the fire has been uploaded to YouTube by Gamer's Light.