To illustrate my story, here is a photo of my CZ, going west over the Rock Creek trestle on August 23, 1969. Note that behind the power is an SP all room car, a 12 bedroom car, I believe, being deadheaded out to Oakland. And behind the CZ baggage car is that GN 16 duplex roomette-4 bedroom car that showed up in Drew's photo, which may well have been taken the very next day.
(Why the deadhead SP car? I'll speculate that the 6 bedroom-5 compartment CZ car was bad ordered in Oakland on the prior cycle, and WP borrowed the car from the SP to subsitute it for a round trip or two. The car may have been in service eastbound, but is deadheaded back westbound with a replacement 6-5 CZ car in the consist. Whether that's true or not is unknown - but at least its logical! I saw an eastbound CZ in April of 1969 with an SP 12 bedroom car in this very service.)
Lee Hower
Sacramento