The opening shot of the railroad workers tunneling through the hillside was filmed on a bluff above the backside of Bronson Caves in Griffith Park, Los Angeles. These man-made caves (the site was once a quarry) have been a popular film location over the years, most notably as the entrance to the Bat Cave in the original Batman TV series. The site has since somewhat fallen into disrepair with constant erosion and rockfall and the caves are no longer open to go inside. You can see how the passage of time has nearly buried the entrances.
GPS Coordinates (bluff): 34.121369, -118.313091
This is the same spot at ground level. There is also a great view of the Hollywood Sign from here!
Later in the episode, Brisco follows one of Bly's gang members to the entrance to their underground hideout. This was also shot at the caves, from the north side.
GPS Coordinates: 34.121782, -118.313388
Our introduction to Brisco was filmed on the backlot at Warner Brothers Studios Burbank, in an area known as "Laramie Street." Unfortunately this was torn down in the early 2000s to make room for updated sets.
The "Westerfield Club" - seen throughout the series in this same establishing shot - is the Embassy Courtyard of Warner Brothers Burbank's New York Street.
GPS Coordinates: 34.149234, -118.337464
The cafe where we first see Lord Bowler was shot on "Hennesy Street" on the Warner Brothers Burbank backlot. This popular filming site can be seen (when not in use) on the excellent Warner Brothers Studio Tour.
Brisco and Socrates end up dangling from a building and falling into a hay cart. This was filmed on "Midwest Street" on the Warner Brothers backlot. This building looks almost exactly the same today.
GPS Coordinates: 34.148984, -118.336385
A brief shot of Brisco and Dixie's cart was filmed at the former Lyons Ranch (then owned by Warner Brothers) in Santa Clarita. This area has a long history of film & TV production, including most notably Dukes of Hazzard. Today, this site is part of Taylor Trail Wilderness & Open Space Area and can be accessed via a short hike.
GPS Coordinates: 34.364884, -118.567042
(Above photos taken on a visit in 2002)
The town where Brisco and Dixie are taken to by Bly's gang is "Laramie Street," the former old west town in the southeast corner of the Warner Brothers Burbank backlot. This famous site has seen countless film productions, perhaps most notably in Blazing Saddles. It was used heavily in Brisco, seen from all angles, to represent multiple locations. Unfortunately, after years of neglect it was torn down in 2004 to make room for new standing sets.
Scenes featuring the steam train were filmed at Railtown 1897 Historic Park in Jamestown, CA. The locomotive featured is the famous Sierra Railway No. 3, built by Rogers Locomotive in 1891! This impressive machine has been seen in hundreds of films over the years, notably in Back to the Future Part III. At the time, the train ran a much longer route than it does today so unfortunately many of the specific filming sites (also used in BTTF III) cannot be seen. Still, this park is still well worth a visit to see these steam machines in action!
Also, Railtown houses an exhibit all about the use of its equipment in film productions which features props and setpieces created specifically for different productions. One highlight is the fake scenery that was supposedly painted on the boulder, which featured prominently in this episode!
The scene where Brisco tries out the professor's rocket car were filmed on the south end of the railroad yard at Railtown 1897. The Petticoat Junction water tower can be seen behind him. While not accessible to the public, this spot can be see from the excursion train.
The railroad trestle scenes were done utilizing the creative use of miniatures, as no such bridge still exists on the Sierra line.
The cliff scenes were also shot using miniatures (fairly obviously).