Evaluation is the first step in repairing a model locomotive. A person can’t repair what they you don’t understand, and if something isn’t broke, don’t try to fix it. Evaluation allows me to discover what is and what is not wrong with a locomotive. Often the evaluation phase indicates cheaper alternatives. For example, instead of a buying a new motor, a balky original motor may only need a good cleaning and fresh lubrication to smooth it out. If I can make the model run better by straightening or adjusting worn parts I do not recommend installing new parts.