The locomotives used are General Motors SW-1500 diesel switcher units. The diesel locomotive coupled to the passenger cars at the opening is likely an EMD E8 or E9 passenger road locomotive. The locomotive and the cars bear the colors of the Union Pacific railroad, and the extensive location work was filmed at the Union Pacific yards in Los Angeles.
This is the first show to employ the "false" journey, which would become a "Mission: Impossible" trademark. Later shows would vary the method from truck to airplane to submarine.
According to episode director Ralph Senensky on his official website "Ralph's Cinema Trek," this segment was submitted for Emmy consideration in 1967 and won the award for Outstanding Dramatic Series that year.
This is the final episode of the first season to reuse footage from Memory (1966) for the dossier scene. As a result, while both Dr. Selby and Oliver Donovan are selected for the mission, neither man's dossier appears in the pile with the regular cast. Finally, as in the other three episodes to re-use this footage, we see Joseph Baresh's dossier on the top of the pile when Briggs has finished selecting the team.
After being completely absent from the previous episode The Train (1967), Dan Briggs plays a limited role in this episode. He is seen in the tape scene, the dossier scene and the apartment scene, but not in the field while the mission is underway.