Classic movie silliness

There is a promo for a segment on our local news this week featuring a scene from an old silent movie (or a facsimile of an old silent movie) where the villain ties the girl to the train tracks and it has me wondering: what is up with that? This is such a standard image and I never really thought about it before, but what does the villain hope to accomplish by tying up the heroine? Is he stalling the hero so he can commit crimes while the hero is busy freeing the girl? This seems unlikely since the villain is usually driving the train, so is he just sadistic and wants to see girls squashed? Seems like an awful lot of trouble, especially since the fact he has to walk or ride his horse all the way back to get his private train that he then drives towards the girl always seems to take so much time the hero can of course rescue her. I guess it didn’t matter back then because movies were so fascinating people would watch anything (seriously – I have seen what is basically home footage from the early 1900’s of a baby eating that lasts over an hour. wheee). Still, it’s a pretty weird plot element.