In 1975, the National Park Service embarked on a project to reproduce the Union Pacific No. 119 and Central Pacific Jupiter exactly as they appeared in 1869. Since the original drawings had not survived, the Park Service initially approached Walt Disney Studios, which had previously built two steam engines from scratch for their Disneyland park's railroad, for the project. Disney declined, but recommended the O'Connor Engineering Laboratories in Costa Mesa, California, for the task.

Noted railroad historian and steam engine owner Gerald M. Best served as engineering consultant to the Park Service for the project. Over 700 detailed engineering drawings were recreated, based almost entirely on the photographs taken of the engines during the ceremony. Disney animator and steam engine owner Ward Kimball did color matching and original artwork for the Jupiter and No. 119.

And you know I got lots of movies too:
Part 2 - [ youtube video ] Golden Spike National Park
Part 3 - [ youtube video ] Golden Spike National Park, Part 2. Antelope Island Sunset shoot