In the recent case in Colfax, UP apparently got a track open soon enough to get #6 to Reno before midnite (not even an 8 hour delay, some of which was made up by the time it left SLC). Maybe that caused some crewing issues but the train got through and completed its run. 7-8 hr late at an intermediate stop (or even the terminal) is nothing for that train - I've seen it days late when Stuff really happens. Passengers were apparently bused from wherever #5 was held to their destinations, and presumably once the track was open the equipment continued to Oakland. Is that a reasonable guess? If the situation resembled that, there was no need to even think about detours or turning either train; just wait a few hours, shuttle out a new crew if necessary, and bring it home on UP's schedule for clearing things. Having the passengers all bused away made it even simpler for the westbound. And it wasn't even stormy - very nice weather.

Especially out West, there aren't a lot of parallel routes, especially maintained for passenger trains. So the comments above about difficulties with detours and short turnarounds are very true. The only detours I've seen have been things like the Starlight via Tehachapi, set up well ahead of time for heavy maintenance that was going to keep the regular route closed for an extended period.