The distinguishing feature of the City of Portland, as of the City of Los Angeles, was its dome diner. The COP’s competition, the Empire Builder and the North Coast Limited, had plenty of domes, but no dome diner. The COP also offered a late afternoon departure from Chicago, convenient for passengers connecting from day trains, whereas the Builder and NCL left Chicago in early afternoon. The COP was faster for Chicago-Portland passengers, and, for much of its life, carried a through sleeper to Seattle that got passengers there as fast as either of its competitors.
The Union Pacific brochure reproduced above and below is dated 9/59. It shows the dome lounge being run on the end, as an observation car, as indeed it was built to be; but the car soon would be moved to mid-train, behind the dome diner and in front of the sleepers.
Union Pacific was among the leaders in publishing beautiful brochures about its trains.