For proper identification, which combination is required?

• A. Initial and engine number only
• B. Train number and destination
• C. Initial and number of the engine
• D. Engine type only

Answer: (C)

Locomotive identification relies on a unique tag: the initials (the railroad’s reporting marks) and the engine number. The initials show which railroad owns or operates the engine, while the number singles out the specific locomotive within that railroad’s roster. This combination is used across logs, dispatch, maintenance records, and safety communications to refer to one precise unit.

The train number and destination describe a service rather than the particular engine, so they don’t uniquely identify a specific locomotive. Likewise, knowing the engine type alone doesn’t distinguish between multiple units of the same type. Therefore, using the locomotive’s initials together with its engine number gives a definite, unambiguous identification.