Charles Aidman was added to the cast to fill in while Ross Martin was recovering from a mild heart attack.
Rory Calhoun was originally cast to play Jim West.
Miguelito Loveless' middle name is Quixote.
Jim West's birthday is July 2, 1842. He was named after his father's brother.
Jim and Artie had two different trains. The first was a dark-paneled model used in the seasons the show was filmed in B&W. The second was a more functional model decorated in green and gold. It's this train, which houses the unique gadgets associated with the show, that most people remember.
Jim West was a captain in the army before he joined the Secret Service.
The series was ultimately canceled due to CBS being uncomfortable with the "excessive" violence of the series, rather than declining ratings.
Though Richard Markowitz wrote the theme, he wasn't credited for it on any episode of The Wild Wild West or on The Wild Wild West movie.
The name of Jim and Artemus's rail car was The Wanderer 1.
Miguelito means "little Michael".
Robert Conrad did all his own "fight choreography", including the stunts, until he almost killed himself when one of them backfired.
Robert Conrad (5'8") wore 3" heels as Jim West and the CBS casting office had orders not to hire any women over 5'6" for the show.
Ross Martin read the script. Then he did a pen and ink drawing of the character he was going to play, down to the last detail, glasses, mustached, clothes, posture, shoes, etc. Then he brought sketch to make-up man Don Schoenfeld, and together they molded his face until it looked like the drawing.
The only episode whose title doesn't begin with "The Night..." is "The Wild Wild West" (1965) {Night of the Casual Killer (#1.5)}.
The show was originally titled "The Wild West West" but was renamed when it was decided that The Wild Wild West sounded better.
Three veterans of The Wild Wild West, stuntman Whitey Hughes, makeup artist Ken Chase and actor Richard Kiel, reminisce about the series and star Robert Conrad in the book "A Sci-Fi Swarm and Horror Horde" (McFarland & Co., 2010) by Tom Weaver.
All the action that took place inside the train was shot on a set in the studio. The "car" had removable walls so that the camera could maneuver. This is especially obvious when someone is coming in or going out since there is always a bush visible outside which blocks the interior of the sound stage. Even when the long shot shows a desert with nothing around the car the bush is still seen.
The recurring science fiction theme, where genius scientists in the 1870s invent technology which didn't exist in the real world until decades later, has come to be called "steampunk," a term coined in the 1980s.
The pool table seen in James West's train car was made smaller than regulation size in order to better fit into its surroundings.
Though shown as the second episode, this was actually the ninth episode filmed.
While muscleman Dan Vadis shaved his chest for roles in Italian "Hercules" movies, here -- as Dr. Loveless's bearded wrestler -- he appears with a full growth of chest-hair.
Major guest stars Michael Dunn and Leslie Parrish both had guest starring roles on the original '_Star Trek_(1966)' TV series. Dunn appeared in "Star Trek" (1966) {Plato's Stepchildren (#3.10)}, and Parrish in "Star Trek" (1966) {Who Mourns For Adonais? (#2.2)}. Both episodes had titles and plots concerning ancient Greek culture.
In the restaurant, Artemus mentions the smell of Prussic acid. This is an old term for hydrogen cyanide, the well-known poison. This term came about because hydrogen cyanide was first isolated from a dye known as Prussian Blue.
This is the only The Wild Wild West episode whose title doesn't begin with "The Night...", instead it is simply "Night of the Casual Killer" omitting the first "the".
According to the audio commentary provided by Robert Conrad on the DVD, Ross Martin actually played the musical piece on the violin during the opening scene of this episode and adds that Ross Martin was a concert violinist "in his younger days".
Artemus compliments Amelie Charlemont's cattleya occidence. Cattleya is a genus of orchids containing 113 species (although none of those species is named occidence), and is the variety generally considered by most people as the "typical" orchid.
The "detector" used here to show the presence of franconium is actually a Crookes radiometer, a device in which the vanes revolve when exposed to visible light. It was invented in 1873 by British chemist chemist Sir William Crookes, and continues to exist to this day as a novelty item. Other types of radiometers are activated by other types of electromagnetic radiation.
The name "franconium" suggests an element, but it is described as a "chemical", suggesting a compound of some kind. There is an element called Francium; its existence was predicted in 1870 on the basis of its position in the periodic table, but was not positively identified and named until 1939. It was the last naturally-occurring element to be discovered and is the second-rarest element, with only 30 grams in existence at any given time in the entire Earth's crust.
The villains of this story belong to a group called the Camorra. This group actually existed in the past and may have been a forerunner of the modern day Mafia.