Before beginning we have one word of caution to offer.
Don't do your work in a hurry. Don't calculate on the length of time it is going to take you to do it. Make up your mind to understand each detail before you begin, and to work slowly and carefully.
If you remember this you will probably be able to build your locomotive. If you forget it you certainly will fail.
How to Begin.
First of all in building a model locomotive, as in every other class of engineering work, it is necessary to get the measurements correct in spacing out the different parts to be joined together; and do not think that because it is only a model you are making that any off-hand way will do, because you will find before the engine is half finished that great accuracy is necessary if you wish your model to work.
A slight mistake in the measurements of a large engine will cause so much friction as to take half its power to overcome. The same mistake with your model will stop it entirely.
In soldering be careful to get the metal thoroughly heated. You will then get a firm joint—otherwise not.
| Fig. 1. | Fig. 3. |
| Fig. 4. | Fig. 6. |
In giving these directions we assume that the boy who will undertake to follow them is accustomed to the use of tools to some extent. If not, he will have to learn as he advances by repeated experiments.