Factual error: In the final scene, where Fonda and Holbrook are looking over the carrier at the crowds on the dock, you can see that only the first rows of people are dressed in period clothes. The rest of the crowd are dressed as they would have been in 1976 when the film was made. Also, between them in the background is a yellow Ford Pinto.
Factual error: The train consists of nine cars - six RIC cars of the Swiss Federal Railways (two 1st class with nine compartments each, two 2nd class with eleven compartments each, one 2nd class with twelve compartments, and one dining car between the classes), an MU sleeping car belonging to the CIWL (International Dining And Sleeping Car Company) between the two first class coaches, and at each end one older Swiss baggage car. The first class has 108 seats, the second class has 204 seats, and the sleeping car has 36 berths; so the train has space for 348 passengers - or 400, adding the 52 restaurant places. I wonder where they put 1,000 people on this train.
Factual error: When the Petrox engineers dump Kong into the pit filled with chloroform they haven't knocked him out - they've killed him. Chloroform vapour is heavier than air so Kong is breathing it in a pretty pure form - and it is lethal in concentrations as low as 40,000 parts per million. In the time it would take to render a gorilla unconscious by this method, it would die. This ignores the fact that liquid chloroform is a severe irritant and a contact poison, and its breakdown products include phosgene and hydrogen chloride, both deadly poisons. They might as well save themselves some time and use that dinky little bulldozer to fill in the pit.
Factual error: Supposedly the Pantera was rigged to explode once it reached 160 mph. There are two problems here. First, a stock Detomaso Pantera could never reach 160, especially a smog-controlled "L" model with the old bias-ply Arriva tires, which is what they used in the movie. Second, the Dodge Polara police car that was tailing him closely and matching his speed, most DEFINITELY would not be able to achieve that speed.
Factual error: When Richard Kiel is shooting at Gene Wilder on the train, you hear the "ping" of a "silencer" on the gun. However, Kiel is shooting a .357 magnum, which cannot be equipped with a silencer.
Factual error: When Harry shoots the last badguy in the tower with a LAW, the safety of the weapon is still on. The pin to arm it has to be pulled out. If it were armed, you would see a little pin, instead of little block, between Harry's little finger and his ringfinger. (01:28:35)
Factual error: The gatling gun that Josey Wales uses had the options of a 40 round magazine, or a 104 round drum magazine. Neither Josey or the Red Legs ever bothered to reload the weapon. The gun would have been empty after the 10 barrels revolved at most 10 times. Josey alone shoots for a couple of minutes straight.
Factual error: In the scene where Julie, the secretary, has been discovered dead; the lieutenant approaches her, kneels down, and checks for a pulse with his thumb. As anyone with any medical knowledge should know, if you attempt to take someone's pulse with your thumb, you will get your own pulse and not the victim's.
Factual error: At the start of the movie, the nuclear-powered articulated bus that is attempting a non-stop land run to Denver leaves New York City, but you can see the Rocky Mountains in the background.
Factual error: In more than one scene you can hear the sounds of a steam locomotive chugging and blowing the whistle. Steam locos were almost entirely phased out by the early 60's, and none ran in Philadelphia at the time this movie was made.
Factual error: When a Rear Admiral and Captain are walking together, the Captain's epaulets are the wrong way round. A cardinal sin in the Navy. (01:30:00)