Ah yes. Thanks for clarifying. UP's original line into Spokane, before the days of Joso Bridge and the Harriman-style modern main line that came into Spokane via Marshall Canyon. The difference in decades explains the severe serpentine nature of not just Mica Hill, but also the surviving UP trackage from Manito south to Fairfield, which is also part of UP's original Spokane main line.

As for Mica Hill, I should have said "previously part of MILW's secondary main" instead of "originally." Had MILW actually been the outfit to build down that opening into the Spokane Valley (assuming that's where they would have gone), I wonder how differently they would have engineered it.