engineman

Short definition from Wiktionary

Noun

1. 1
   A man who operates, manages, and maintains an engine.
2. 2
   A man who operates, manages, and maintains an engine: A locomotive engineer; (sometimes) any footplateman.
3. 3
   A man who operates, manages, and maintains an engine: A navy sailor who operates, manages, and maintains engines and various other shipboard equipment (such as one with the United States Navy EN occupational rating).