This movie in a way was The Duke's farewell to the western genre as he plays an aging gunfighter just trying to hang it up and die in peace. The film was mostly shot at Warner Brothers Burbank studio. 

The film has a blink-and-you'll-miss-it shot of a steam engine in one shot (far left) - deep in the distance. This is the Eureka & Palisades #4 "Eureka," a 4-4-0 from 1875 that was owned by Warner Brothers from 1939 until the end of the 1970s. This film was it's final film role (to date). The bustling town of Carson City is actually Midwest Street on the Warner Bros Burbank backlot, which still looks very similar today (sans streetcars). The tracks that the streetcar runs on were used previously by the Eureka in Cheyenne Autumn.

As for the Eureka, it ended up in private hands in Nevada and has been lovingly cared for in the years since, making rare public appearances at events such as the "Steam Up" in Carson City at the Nevada State RR Museum. If you get the chance, it's well worth it to attend and see this beauty in action!