Got a cab ride in a GP40 on Tennessee Pass (down the hill) once. Was lead unit of a set of helpers (GP40s, 30s, and 35s). Was at night and no bosses around.
Almost got a ride once on the Monarch branch in 81. Engineer was about to invite us on for a ride from Monarch down the switch back (we would have had to walk back to our car at the mine, but it would have been worth it). Conductor came up and nixed the idea. In addition he cussed at us for taking his picture and threatened to throw something at us if we took another picture of his caboose. Wife must have given him a hard time at breakfast.
Would have loved to see or ride a train on the Ibex branch out of Leadville. Highest line on the D&RGW and really something...switch backs, double loops, etc. Was standard gauged in 1917 and abandoned in 44, but the right of way is still pretty much intact with some ties still in places that have not been made into a rode. Would have been a wild ride indeed.