Haven't followed the Foss tug business closely since this ended. I do know there's other business on the lake and St. Joe and Spokane rivers that requires occasional tug service to move barges carrying cranes and other equipment to hard-to-reach work sites. Without plowing through my books, I can't say I'm aware of which interurban line would have been a proving ground for GN in the Cascades. GN's mountain electrification has always interested me, but it's not something I've done much research on. What you had in the Inland Empire was a cluster of lines that at one point became unified under banners like Spokane & Inland Empire; Spokane, Coeur d'Alene & Palouse; and other names. Main routes being Spokane south into the Palouse and Spokane east to CdA. These later became GN branches. In CdA, the brick building that once housed the battery substation for the electrification is now home to the Human Rights Institute. There was much talk over the past 20 years about using some of this track as a downtown trolley, but the developers, college, and some easily-bought civic leaders are pushing to rip out every inch of track ASAP and cover the land with new buildings.