According to a news item in the Hollywood Reporter, Cecil B. DeMille directed much of the film from a stretcher, because of an operation he had months earlier. However, studio records indicate DeMille collapsed from the strain of directing three units simultaneously, and used a stretcher for about two weeks.
Dick Allen (Robert Preston) asks, "Where does he keep his 'Rule G'?", meaning a bottle of whiskey. This is a reference to Rule G: "The use of intoxicants or narcotics is prohibited", one of twelve 12 rules in standard code adopted by the Association of American Railroads.
For the Indian attack on the train, Paramount hired 100 Navajo Indian extras.
In order to operate the number of trains required by the production, Paramount had to get a regulation railroad operating license from the Interstate Commerce Commission.
One of over 700 Paramount productions, filmed between 1929 and 1949, which were sold to MCA/Universal in 1958 for television distribution, and have been owned and controlled by MCA ever since.
The company had rented many local pinto horses for the filming of the Indian attack on the train. During filming, however, local cowboys had to be hired to round up the horses, as they would scatter and sometimes stampede because of the noise and confusion of these scenes - all the shooting, yelling, and yards of unfamiliar cloth on the horses, along with kettles and other implements tied to their manes and tails, made them extremely nervous and uncomfortable, and it didn't require much to make them bolt.
The gold spike used at the ceremony to mark the end of the construction was the same spike actually used in the May 10, 1869 event, on loan from Stanford University.
The world premiere in Omaha, Nebraska, was a three-day celebration that drew 250,000 people, doubling the population of the city and requiring the National Guard to help keep order. The special train en route from Hollywood to Omaha, carrying Cecil B. DeMille and stars Barbara Stanwyck and Joel McCrea, took three days and made stops along the way, drawing large crowds. The film was shown in three theaters simultaneously; President Franklin Delano Roosevelt was reported to have started the premiere proceedings by pressing a button in Washington, DC, which opened the civic auditorium. An ad stated that the premiere, which involved parades, radio broadcasts and a banquet, was the biggest in motion picture history. An antique train continued on a 15-day coast-to-coast promotional tour, stopping at 30 cities around the country.