Pete Bracken's train, hauled by the "Texas", was actually 21 cars long, rather than the 2 cars depicted in the film.
The Yonah, in this film was portrayed by an early 1920s reproduction of an 1830s engine of the 4-2-0 wheel arrangement. The real Yonah was a 4-4-0 engine, as were the General and the Texas, and was built in 1849. Moreover, the real Yonah featured a headlight and cowcatcher, which the one in the film lacks.
The General and Texas feature cowcatchers with vertical wooden slats rather than those with horizontal strap iron ones which the railroad used exclusively until the 1870s.
The real General featured a three-dome configuration and ankle-rails instead of running boards during the war. The film General more closely resembles the real one's post-1890s appearance.
The Confederate major told the Captain that all the captured raiders would be hung. This did not happen. Six were later used in prisoner exchanges including Pittenger and Buffam. Pittenger was later promoted to sergeant and Buffam to second lieutenant.
In the long shot of the Texas running in reverse toward the tunnel, it is obvious by the unnaturally quick movements of the crew that the film has been sped up.
The coaches used in the film feature a duck bill style clerestory roof. While clerestory roof coaches existed in the 1860's they would have been of the monitor style. Furthermore, the Western and Atlantic Railroad was most likely still using the older style radial roof coaches in 1862.
The switches shown are of the point blade variety which were not used before the 1880's. Thw switches on the Western & Atlantic would have been stub switches in 1862.
The locomotive "William R. Smith" which Fuller commanded to recapture the General from Kingston was from the Rome Railroad, not the Western & Atlantic Railroad. The real William R. Smith's tender has the word "Rome R.R."
Robert E. Lee did not take command of the army of Northern Virginia until 1 June 1862; 1 1/2 months *after* the locomotive chase.
In reality, the Catoosa locomotive from Calhoun Station had joined the Texas to pursuit the General instead of doing nothing but parking on the side. In the movie, the Catoosa didn't chase the General with the Texas.