Nearly all of the StL&NA activities start with a fully coaled/watered engine. I was wondering if there is an optimum fill - Obviously running out of water with steam is a disaster - So do you fill her up to the top whenever you can - Or is it take what you need to do the job. Does it vary with engine?

Do tank engines that carry there own coal/water need any of it as ballast to improve traction?

Also is there a level that you wouldn't / couldn't go below - for instance is all the water in a tender accessible or do some tender designs limit you. Also does sludge accumulate reducing what's useable.

Thanks for your patience.

Guess I'll take a stab at this:

"So do you fill her up to the top whenever you can - Or is it take what you need to do the job. Does it vary with engine?"

General rule is you fill up when you can. That way, if there's a delay, derailment, whatever, you should have plenty of juice. There are exceptions to every rule. When it's real hot out, nonlifting injectors can be cranky with warm water. To get around this, engine crews put a hot engine away in the house with just enough water to stay topped off during the night. Then upon leaving the house the tender is filled from the water tower, which tends to stay cool no matter how hot it gets. That way the engine starts its day with a cool tender of water. You get the picture.

"Do tank engines that carry their own coal/water need any of it as ballast to improve traction?"

Yes. And tank engines need to dump their water and get a fresh load in the morning for the above reasons. The water in the tank can get really hot in the house, foiling both lifting and nonlifting injectors. Tank engines have tremendous pulling power comparable to a locomotive of the same pressure, engine arrangement and wheel configuration that tows a tender.

"Also is there a level that you wouldn't / couldn't go below - for instance is all the water in a tender accessible or do some tender designs limit you. Also does sludge accumulate reducing what's useable."

Any railroad with half a conscience cleans out the tenders on an annual basis, sometimes more, depending on lack of water quality. But standard operating practice requires at least a quarter tank. Injectors are sensitive and susceptible to clogging, but the main reason is the constant spectre of a catastrophic crownsheet failure. I've seen at least a dozen historical photos of a locomotive frame, running gear and tender just shy of the water tank or even at the water tank, with the boiler and cab dozens of yards away in the woods ... Nosirree, Mr. Goddard didn't invent rocketry. Hapless engine crews beat him to it.

Hope this helps.

Though I was around steam and ran steam via a tourist line for a few years, I would certainly respect Steve's concise explanation of rationale for taking on water. I suspect he has had more experience on/around steam that I have, and his is experience is current to boot.

As for the line I worked, we took on water in the morning and once (or twice?) during the day. We added treatment each time, as I recall.

FWIW: We would also sand the flues the last run of the day. I loved doing that! Talk about stack talk!