They sit on a spur of test track outside General Electric’s locomotive factory in Erie, Pennsylvania, panting and grumbling like two old lions half asleep. The ominous, muttering rumble is the sound of 8,800 horsepower at idle—24 cylinders with pistons big as buckets, turbochargers the size of washing machines, two V12 engines direct-driving alternators five feet in diameter.

I need to find out, once and for all, how big it is. I need to see if I measure up to the other guys, if I have what it takes. And to do that, I’ll have to hang it out in public, let them size it up, in a very open display of the one quantity most important to the American car guy. Horsepower.