Maybe this one is up may alley in more ways than one? Seems it's not on the Cumbres & Toltec, but the terrain seens close. It doesn't follow a major watercourse, either.
Dude, for once, this one I haven't seen before. I have searched Montan, CO, and parts of Eastern OR/WA. Yikes, this nearly has me stumped.
Cool, a hint. Good old USA. I have been looking more south of that from California over to the Texas Pan Handle. The old D&FW in eastern New Mexico goes through some very similar stuff just north of Folsum to the Colorado boarder. But allas, no tunnels.
I have checked Raton, LaVeta, Moffat, Craig Branch (that was my original location idea), Siskiyou, Pipestone, Homestake, Mullan , Cumbres, Montrose branch/Passes... I need to check Tehachapi again; does Cajon have tunnels? I'll be this is some obscure shortline.
North of Albin Wyoming http://maps.google.com/maps?ll=41.481404,-104.09789&z=13&hl=en&t=h I just zoomed out and looked for states that looked colorless. Utah and Wyoming stood out. Then I just looked closer.
I worked my way up through Nevada, Utah and Western Wyoming. I was headed that way. Congrats Curn. Man there is a lot of desolate country along the UP route of the City of Los Angeles.