Goofs

Although the cars were full of soldiers, as the troop cars go off the track, break up and slide down the hill, there are no soldiers visible through the open windows and doors.

While the sergeant is turning the brake wheel on the caboose in closeups, in longer shots as the cars pass, there is nobody on either the front or rear platform of the caboose.

Whenever we see the train from the outside it's moving rather slowly, but whenever we look out the windows from the inside it looks as if it's doing over 50mph.

There are two explosions where no one (Deacon or Major Claremont) had set any dynamite.

The amount (and existence) of Deakin's beard stubble is inconsistent throughout the movie.

The stovepipe of the caboose faces the front of the train. Cabooses are always positioned with the stovepipe to the rear so that smoke doesn't blow into the cupola.

Marshal Pearce claims to be both a Deputy US Marshal and an Indian Agent; both are federal appointments that would have entitled him to access to any US Army facilities in the West. Yet Major Claremont initially refuses him access to the train because he is not on "army business."

When Marica notices that the rear cars have detached, she sees a modern AAR coupler (itself an anachronism), with the knuckle opened normally. It is not possible to open a coupler when the train is pulling upgrade. A later shot shows the knuckle broken off. This cannot be done intentionally, and if it were unintentional, the air brake connections would not have been closed, so the brakes would immediately set.

Jill Ireland did not smell the smoke from the burning rope.

The rifles are clearly of various ages due to condition, indicating they are prop stock, but based on model and the year setting of the story, they should all be brand new.

Marica boards the train to visit her father in Fort Humboldt. Her fiance Gov. Fairchild had no apparent reason to allow this, because he knows the diphtheria epidemic at the fort is a hoax, something Marica would learn when she gets there. Since the full scope of the evil plot is never actually revealed - only Deakin's hypothesis of it - most seeming logical holes in it cannot be considered goofs.

There is not a single body to be seen in the shattered wreckage of the troop cars, even though there were dozens of soldiers aboard.

"Dead" Dr. Molyneux draws a quick breath while Deakin is hiding the telegraph equipment in his compartment.

When the rail cars carrying the troopers crash is very clear that all empty. Not only are no "bodies" shown, but none of the soldier's supplies or even their bedding are shown being strewn about the crash site.

During one of the several fights on board the carriages, the scenery outside the window is seen to undergo a jump cut, revealing that the back projection loops have gone full circle.

The "Indian ponies" are all shod. American Indians rarely had blacksmith facilities available, so their horses were nearly universally unshod. Even horses stolen in raids eventually lost their shoes and these were never replaced.

When Deakins comes back up from examining the brakemans's body he is breathing normally. After climbing the side of the deep ravine he should be breathing heavily.

The film (and the novel it is based on) is apparently set in the Nevada "Territory" some time in the 1870s or 1880s, based on the dialogue and equipment in the film (weapons, the steam locomotive, etc.) Pearce is an Indian Agent for the "territory" and Fairchild is the Territorial Governor. In fact, Nevada became a state in 1864.

There were telegraph wires back in the 1800's, but in the scenes where the train is going backwards, high powered electrical lines can be seen in the background.

Saddlehorns and stirrups can be seen from under the Indian blankets on horses.

The locomotive and all the cars have automatic couplers and air brakes, neither of which were in general use until the 1880s.

Both passenger cars have enclosed vestibules (end platforms) and steel underframes, which were not common practice until the early 1900s.

When O'Brien (Charles Durning) climbs aboard the engine to drive the train, a hand reaches out from the right to grab his shoulder and hold him in place even though there is supposedly no one else on board.

In the entire movie the train is traveling up the mountain, but when we see the train running beside the river the current is moving the same direction as the train.

At no time was there ever a Fort Humboldt in the State or Territory of Nevada. There was a Fort Humboldt in the present-day city of Eureka, California, but that was on the Pacific Coast, far away from the gold and silver mining activity in the Sierras and from the native range of the Paiute Indians.

The villains in the plot commit a large number of murders, including the mass murder of the relief troops in the rear cars of the train. Levi Calhoun kills the Army telegrapher at Fort Humboldt in cold blood. Yet they keep all the remaining soldiers in the fort as live captives, conveniently allowing them to be quickly freed and re-armed in time to aid Deacon and Major Claremont.

Dr. Molyneux claims he is immune to diphtheria because he contracted the disease himself. Diphtheria immunity, whether from contraction or immunization, lasts only ten years or so. Dr. Molyneux would surely know that, but he doesn't qualify his statement by saying he had contracted the disease recently.