Designed as a pocket-friendly reference manual for railfans, modelers, and historians to identify North American diesel-electric locomotives by external physical features. Features detailed entries for locomotives produced by major manufacturers—including Electro-Motive Division (EMD), General Electric (GE), American Locomotive Company (ALCO), Baldwin, Fairbanks-Morse, and Lima—as well as specialized industrial unit builders. Includes model designations, horsepower ratings, production years, engine configurations, and unit production totals.