Over time, I realized that for my dad, it wasn’t finishing the train that he liked. It was the years of labor: the days at the lathe, the thousands of hours at the drill press and milling machine. I don’t have many memories of watching those trains run. What I remember are all the times he excitedly called me down to the basement to show me a piece he’d just built—a piece that, when connected with fifty others, might amount to a single axle.