Hi Line Subdivision

The Northern Transcon, a route operated by the BNSF Railway, traverses the most northerly route of any railroad in the western United States. This route was originally part of the Chicago, Burlington and Quincy Railroad, Northern Pacific Railway, Great Northern Railway and Spokane, Portland and Seattle Railway systems, merged into the Burlington Northern Railroad system in 1970.

The section between Shelby, Montana and Whitefish, Montana is a playable route in Microsoft Train Simulator.

The route starts at Chicago and runs west across northern Illinois to the Mississippi River. It follows the eastern shore of the river through La Crosse and Prairie du Chien, Wisconsin before turning west again in Minneapolis and St. Paul, Minnesota to Casselton, North Dakota. From Casselton the route runs northwest to Minot, North Dakota, then west through Montana and Idaho to Spokane, Washington.

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Wikipedia