This postcard illustrates a very unusual car. In 1953, Union Pacific replaced the pre-war City of Denver with modern equipment. Most of the new cars were conventional, with coaches and sleepers easily exchangeable with nearly identical cars on other City trains. But the diners were found only on the City of Denver.
Instead of fitting both the kitchen and dining room into one car, UP ordered two twin-unit cars from American Car & Foundry in which one car held a kitchen and dormitory for train crew while the other car consisted solely of a dining room. The room could seat 66 people, far more than an ordinary diner which, with four-across seating, could serve 48 people at one time.
In 1937, UP had a few twin-unit diners built as part of the original M-10002 and M-10003 streamliners (which initially were the City of Los Angeles and City of San Francisco). But these were shorter cars with a much smaller dining capacity. Apparently, the City of Denver was the only Union Pacific train where the demand for dining car services was so great that a 66-seat diner was considered necessary. Unlike articulated twin-unit diners, which shared a center truck, the City of Denver cars each had two sets of wheels, as shown in this black-and-white photo, but were semi-permanently coupled together.
As the above postcard shows, the interior walls above the windows featured murals showing Denver and the eastern Colorado plains. In addition, the menu being studied the woman by on the left has the Colorado state capitol building on the cover. This isn’t in my collection of UP menus and it raises the question of whether UP had an entire series of menus dedicated to western state capitols, just as it had a series dedicated to state universities. Update: I’ve added the menu shown in the postcard to my collection.