The Colonel asks a former West Point cadet to salute him inside a train. In military customs and courtesies there is no saluting inside, unless reporting.
The film revolves around the Washington Flyer, a train that goes from New York to Washington. But there was NO train that went from New York to Washington in 1861. To get to Washington from New York, one first had to take the train to Baltimore, where the line terminated at the Presidents Street Station. One then had to take a carriage 10 blocks west to Camden Station. It was here that the line to Washington began. There was NO connecting service except by carriage (or walking). This is why the first blood of the Civil War took place in Baltimore. When the 6th Massachusetts was making its way from Boston to Washington, they had to march from the Presidents Street Station to Camden Station to get to Washington. It was during this march on April 19, 1861, that an angry mob of pro-secessionists attached and killed 5 soldiers and wounded 36 more while suffering 12 killed and scores (perhaps even hundreds) wounded themselves.
The secessionists of the South were Democrats; however, the movie portrays the secessionists as Republicans. The Tall Target, Abraham Lincoln, was a Republican. No wonder the movie opened by saying this dramatization was disputed.
The opening credits include the usual disclaimer: "The events, characters and firms depicted in this photoplay are fictitious. Any similarity to actual persons, living or dead, or to actual firms, is purely coincidental" But the entire story revolves around an assassination plot against President-Elect Abraham Lincoln, who is depicted on the screen, with dialogue.
In spite of being set in 1861, there are electric lights hanging in the station and in other locations.
George Pullman created the "Pioneer", his first sleeping car that contained folding upper berths and seat cushions that could be extended to make lower berths in 1865, 4 years after this movie takes place. Worse yet, the roomettes shown in the movie didn't come into use until the early 20th Century.
Several of the firearms appear to be out of date. One obvious example of this is the Remington Model 95 pistol, which was released over 4 years after this story was set.
The army officers and enlisted men salute with their palms down. Prior to, and during the Civil War, the army saluted with palms out, British style.
This is an inferred anachronism: A street scene in Baltimore has a vendor selling crabs and lobsters. But the refrigerated car would not be invented until 1878. So, there was no way to get lobsters from Boston to Baltimore without them going bad during the trip.
At the beginning, as the train backs into the station, the bell on the engine is ringing. The train stops and the bell stops as well, but the soundtrack still has the bell ringing. The next scene shows a closeup of the bell ringing which had stopped in the first scene.
The film ends with the train (carrying Lincoln) getting into Washington and passing the Capital (then under construction). But trains from the north terminated at the New Jersey Avenue Station, which was one block NORTH of the Capital. So, south bound trains from the North would NOT have gone by the Capital but would have stopped before getting to the Capital.
When the train from New York arrives in Baltimore, it pulls in next to Presidents Street station from behind and stopped on its left side. But Presidents Street station faces north NOT south. So this south bound train would have approached Presidents Street Station from its front.