RE: “Full Throttle”

My aquacise-instructor has other duties at the Canandaigua YMCA swimming-pool. She also leads pool exercises that include extreme physical exertion: so-called “full-throttle.”
The balance-training I do doesn’t.
That lady is in Hampton Roads, VA, showing her new grandson to her parents and others. The baby’s parents are also along.
She Facebook-posted a photo of herself and her grandson in a swimming-pool. Some wiseacre commented about teaching him “full-throttle” exercises.
Thoughts occurred I didn’t comment.
Railroad steam-locomotives were “throttled.” The amount of steam admitted to the cylinders was controlled by a throttle. Valve-events were also varied. Opening and closing could be limited. Only recently have automotive gasoline-engines started doing that.
Allow a steamer to use too much steam, and it will puke out.
A long linkage connected the steam-locomotive throttle to a large lever in the cab. That lever usually hinged from the cab-ceiling. Pulling the lever back opened the throttle. Wide-open the lever hit the ceiling, which is how we got “throttle-to-the-roof!”
Gasoline engines are also throttled. The mixture of air and vaporized gasoline is throttled. Wide-open throttle permits maximum air/gasoline. To me that’s “pedal-to-the-metal,” the gas-pedal floored. Slang, but the same as “full-throttle.”
Diesel-engines aren’t throttled. The amount of air supplied to cylinders is determined by a supercharger (or “turbocharger”) which pumps and compresses air into the cylinders. The air isn’t throttled.
Diesel power output is a function of how much fuel is injected into those supercharged cylinders. This is true of diesel trucks, railroad locomotives, and also the gigantic diesel engines in ships.
Diesel locomotives have eight fuel-delivery settings. Maximum is “run-eight,” the equivalent of “full-throttle” — except diesel engines aren’t throttled.
Locomotives climbing Allegheny Mountain west of Altoona are in “run-eight” = “assaulting the heavens!”