What the heck are these things called and how do they work? If my title wasn’t explanatory enough I’m referring to those carts on train tracks that work by pumping the handle up and down like a seesaw. I tried to do a search but not knowing the name kind of hindered it. 
They are called “hand cars.” The link shows some pictures. As for how they work: the men pump the handles up and down, like an old-fashioned water pump, and that drives the wheels. A lever adjusts the gearing, changing the direction of the motive force.
I always thought they were just called handcars. I know a guy who built one and would sneak on the tracks late at night…
Yeah, what silenus said.
Thanks guys, mucho appreciated. 
Of course, wherever there’s a vehicle, there are people who want to race it.
That seems awfully dangerous.
That seems awfully dangerous and foolhardy.
Well…yeah. The guy is a train fanatic. He has old signals and stuff in his backyard. He’d use a local track after dark that rarely had night time traffic. The cart was also light enough to get off the track in a reasonable amount of time. It always seemed to me like a Darwin award in the making, although I don’t think he’s done it in 10 or 15 years.
Please tell me he doesn’t yell out “WooooWooooo” as he goes down the tracks.