Edwin S. Porter's "The Great Train Robbery" met with great success, being the first western and one of the first 'full length' (by the standards of the time) movies. So, two years later he thought to parody it, by changing the bandits to children who commit crimes. Thus, "The Little Train Robbery" was made. While the idea is clever at least, there is no medium closeup of the bandit firing at the camera at the end and because of the lack of this, it has not become nearly as well known.
If you've seen the original movie before then you're probably already familiar with the plot: a train is robbed, bandits are caught. The thing isn't even much of a western at all like the original because of the lack of violence (no gun shots are fired and the closest they get is one kid hitting the engineer over the head) and a great deal of it is devoted to the chase scenes, which go on a little too long. It isn't a bad film by any means but lacks the action and attention-holding pacing of its predecessor. Worthwhile for fans of "The Great Train Robbery", but if you haven't seen that yet then you'll have to watch it before giving this one a go.