In the late 1960s, prior to the creation of Amtrak, the Union Pacific Railroad combined its long-distance streamliners between Chicago, Kansas City, and the West Coast into a single massive train dubbed by critics the "City of Everywhere". This train included the "Challenger", the "City of Denver", the "City of Kansas City", the "City of Los Angeles", the "City of Portland", and the "City of San Francisco". At one point, it ran up to 27 cars. The "City of Los Angeles" separated from this behemoth at Ogden, Utah, to serve Los Angeles via Las Vegas. Of these, Amtrak retained portions of the "City of Kansas City" and the "City of San Francisco" for its Chicago – San Francisco service, which it named the "San Francisco Zephyr". Regular service to Las Vegas ended in the early morning hours of May 2, 1971, when the westbound "City of Los Angeles" made its last station stop on its final trip to its namesake city.