Union Pacific introduced the City of Los Angeles on May 15, 1936, and the City of San Francisco on June 14. But it used the front cover of this timetable to feature the City of Denver, which was inaugurated on June 18. Other than the City of Salina (now recognized by that name in this timetable), the City of Denver was so far the only daily streamliner. Note also that the M-10000/M-10001 image on the back cover (shown below) was replaced by the M-10004 City of San Francisco, which was the same design used on later M-1000X streamliner locomotives including the City of Denver.
Click image to download a 47.3-MB PDF of this timetable.
On May 31, the Burlington had pre-empted the UP when it introduced the coach-only Advance Denver Zephyr, which was the original Pioneer Zephyr and Mark Twain Zephyr diverted from their regular routes so Burlington could get a leg up on the Union Pacific. UP naturally responded by advertising that the City of Denver was the “only 16-Hour streamline train with Pullman accomodations between Chicago and Denver.” Burlington’s sleeping-car equipped Denver Zephyr wouldn’t enter service until November.
The front-page ad on this timetable does mention the City of Los Angeles, City of San Francisco, and City of Portland as taking “just one day, two nights en route” from Chicago. They were probably advertised more heavily in a previous timetable. Of course, the City of Los Angeles had to compete with the Super Chief, but the city trains had no peer (and never would) on the Portland and San Francisco routes. I am grateful to Tim Zukas for contributing scans of this timetable.