A regional train was being shunted from track to track in the Garmisch-Partenkirchen train station when one of the wagons rolled away. The car then gathered speed along a roughly 12-mile downhill stretch of track on its way to the town of Ohlstadt.
The rail line was closed for all traffic for approximately two hours. Workers with German rail operator Deutsche Bahn closed all crossing gates all the way and posted warning signs.
An investigation is underway into the incident.