We Captain John Nelson is chasing and shooting at the crooks who stole the dynamite, he passes the same stretch of road twice, with the dead tree on his left, and so do the crooks.
When Nelson offers to rehire the men at the saloon, he starts to pick up the saddle bags from the table. It then cuts to a close-up of him and the bags are laying flat on the table again. In the next shot he is holding them again.
When the troop train approaches for the final battle, it first shows reused footage of the train blown up earlier, which was all freight cars. When the battle actually commences, it has turned into a different locomotive pulling a mix of passenger and freight cars.
When railroad boss Cal Bruce in riding in the train cab and they have to make an emergency stop, the background, from the cab, shows the land is wide open plains, however when the step off the train is up against hills, boulders and trees.
When Capt. Nelson throws the lit dynamite out of the locomotive cab and uphill at the bushwhackers, it's clear that not only does he not have room to throw the dynamite from inside the cab, but also because of the window size and roof overhang, it would be impossible to throw the dynamite more than a few feet out of the cab. The bushwhackers are at least 100 feet away up a hillside behind some large boulders overlooking the track and shooting down at the train.
After firing the cannon several times the boss-man congratulated the men and says, "Now let's get these cannon out of here" whereupon one of the guys grabs the barrel. That barrel would have been piping hot after several shots.
In the montage of the track building after the ambush, there is a brief shot (probably stock footage) of a locomotive lettered "C.P.R.R.", rather than for the Kansas Pacific.
The film is set in late 1860/early 1861 shortly before the outbreak of the American Civil War. The crew building the Kansas Pacific railroad is using dynamite for blasting. Dynamite was invented by Swedish chemist Alfred Nobel in 1866.
When the artillery is shown firing at the locomotive, there is a barbed wire fence running next to the tracks. Barbed wire was not invented until 1867, several years after the time of this movie.
Though the film is set in late 1860/early 1861, firearms used in the film appear to be from 1870s and later. They include lever-action rifles and Peacemaker revolvers. These weapons use modern metallic cartridges. Most weapons of 1860 and 1861 were percussion arms.
The locomotives and all rolling stock are equipped with air brakes and automatic couplers. These were not invented until later in the 1860s and were not in general use until the 1880s.
The passenger cars have clerestory ridges in the roofs, a design feature not available until after the Civil War.
The rocky terrain and the mountains in the background do not represent Kansas.