A Curved Track
means more difficult work on the tramway and cars, for the car must have a movable axle in order to be able to round the curve. But with a straight track the play of the wheel upon the hub should allow enough freedom of motion to overcome the little inaccuracy which may occur in the rails. Experiment will teach you just what is needed. I cannot give exact rules, because the material and location will differ with each builder, and I have found that when I give positive rules, the rules are followed, even when the material and location are entirely unsuited to the directions given. For this reason it is best for each boy to experiment for himself.