The difference is due not so much to the materials of which the locomotive is built as to the method in which they are put together, for no two engines were ever put together geometrically alike.
They may differ in some simple matter. It may be in the casting of the cylinders, in the quality of the copper of the fire box, in the valves or in the smoke stack. Whatever the difference may be there is still always a difference which is bound to affect the running qualities either for better or for worse.
[CHAPTER III.]
HOW TO BECOME AN ENGINEER.
The boy who aims to become an engineer, if he desires success, must make up his mind to two things.
First, that he will, all his life, have plenty of hard work.
Second, that he will, in spite of all obstacles become a good engineer.
A boy who looks forward to the honorable calling should be of robust health and perfect physically. If these conditions do not exist, he should abandon the thought at once, and turn his attention to something else.