Steam Locomotive throttle technique

@PLCProf posted:

I was reading a British book about "Ace Enginemen," the book discusses high points and accomplishments of their various careers during the latter part of the steam era.

One thing that came up repeatedly was throttle technique, some engineers ran with the throttle either open or shut, some used more or less the full adjustment range and a few used the "wee valve" technique leaving the throttle at some partial setting under most conditions.

I understand the thermodynamics of the issue, which basically state that for maximum thermal efficiency you should never throttle the steam flow, but all the engineers in question had received commendations for economy of coal or water, so there is apparently more to the issue than meets the eye.

What was American practice? What are the subtleties I am missing?

Briefly, what you are missing is the relationship between throttle position and valve gear setting. It gets VERY complicated, but close listening to the sounds of the exhaust and running gear should tell an experienced Engineer (Driver in Europe) what he needs to adjust.

Thanks in advance for your insightful comments.

@PLCProf posted:

some engineers ran with the throttle...shut.

How is this even possible?

@smd4 posted:

How is this even possible?

Downhill, with the wind and the sails up.

Rusty

@smd4 posted:

How is this even possible?

Even going down grade, with the throttle closed, surely deprives the valves & pistons of any lubrication. Also, unless the locomotive is equipped with drifting valves, movement with the throttle closed draws a vacuum on the smokebox and thus draws soot/cinders into the valves & pistons.