Dale Robertson, a natural right-hander, taught himself to draw his gun and shoot left-handed, so that his character Jim Hardie would be more distinctive.
The steam engine shown in the series was the number 3 from Sierra Railroad in Jamestown, California, many scenes were also shot in what is now Columbia State Park, both near Sonora, California.
Wells Fargo did have regular and Special Agents, who carried badges, and had some law enforcement powers. Jim Hardie (Dale Robertson), who was a Special Agent, only showed his badge on a few episodes.
The locomotive-tender, and entire train, are the same ones that will eventually become the "Hooterville Canonball".