Identify the required identification elements for trains and engines.

• A. Initial and number of the engine
• B. Engine type and horsepower
• C. Train name and road number
• D. Crew initials and run number

Answer: (A)

Identifying a locomotive relies on two pieces of information that uniquely point to that unit: the reporting mark (the initials of the owning railroad) and the engine number. The reporting mark shows which railroad owns or operates the engine, and the number distinguishes this particular locomotive within that railroad’s roster. Together, they create a unique identifier used in dispatching, maintenance logs, movement worksheets, and on the locomotive itself.

Engine type and horsepower describe the locomotive’s capabilities, not its identity, so they don’t serve as a universal identifier. A train name isn’t a standard, consistent way to identify a locomotive, and road numbers can vary by system but aren’t paired with the owning railroad’s initials in the same way. Crew initials and run number relate to personnel and service, not to the locomotive’s formal identification.