From 1904 to 1970, this segment was part of the Great Northern main line, but it became an isolated branch when the Libby Dam and the Flathead Tunnel were built.
A new source of business in 2016 was transloading magnetite ore destined for coal mines in southeastern British Columbia onto trucks at Fortine.
Originally part of the Great Northern's transcontinental main line, it was rerouted via Whitefish and Eureka in 1904, avoiding the grades of Haskell Pass west of Kalispell.
Farther west and south of Kalispell, the former track toward Marion and Somers has become the Great Northern Historical Trail.
Some of the equipment has been repainted for MMT; other units remain in their original Union Pacific and Milwaukee Road paint.