At least, I think it was an episode of Alfred Hitchcock Presents.
A family is taking a cross-country trip in a train in the dead of winter. The little boy is very rambunctious and the father tells him that he’ll give him a shiny new silver dollar if he doesn’t say a word for one hour (or some period of time). A radio report tells of a patient who escaped from a mental hospital. Efforts were being made to find the poor soul before he died of exposure to the elements. The train is stopped because of an obstruction or something. As it begins to move again, the little boy sees someone (the mental patient) struggling to gain entry through the rear door. The boy wants to tell his dad, thus saving the man’s life; but the father gives him the shiny new dollar to hold and the boy keeps his mouth shut. The hands of the mental patient slide off of the glass at the back of the train and the father says something about learning the value of money.
Okay, here’s the question: What was the name of that episode? (I’ve found some 16mm Hitchcock prints for sale, and I like to see if this is one of them.)