I found this pic on a thresher
website, and I was wondering how do these things
go from horizontal to almost vertical without a
problem? Can someone explain...
(hope it's not too off-topic, after all it is a steam preservation question)

Thanks.



Stvee01@aol.com

Basically, IF the firebox and the majority of the lenght of tubes is covered with water, you're fine. A true vertical boiler (such as on Peppersass at the Cog Rwy in NH) from years gone by has a small portion of the tube length exposed to steam but only after the majority of the heat has been transferred to the water. That space is by design because there's no steam dome on such a boiler. Normally, you look down the stack at the "front" or top tubesheet.

However, putting a traction engine on too steep a grade can cause problems with balance and control. That's at least 10 tons if iron and steel sitting there. Once it starts going where the operator had not intended and as fast as he intended, it's too late to do anyting but run away really fast.

Hope this helps.

> Basically, IF the firebox and the majority
> of the lenght of tubes is covered with
> water, you're fine. A true vertical boiler
> (such as on Peppersass at the Cog Rwy in NH)
> from years gone by has a small portion of
> the tube length exposed to steam but only
> after the majority of the heat has been
> transferred to the water. That space is by
> design because there's no steam dome on such
> a boiler. Normally, you look down the stack> at the "front" or top tubesheet.

> However, putting a traction engine on too
> steep a grade can cause problems with
> balance and control. That's at least 10 tons
> if iron and steel sitting there. Once it
> starts going where the operator had not
> intended and as fast as he intended, it's
> too late to do anyting but run away really
> fast.

> Hope this helps.

On the horizontally boilered engines of the Mt. Washington Cog Railway, the problem was addressed by angling the boiler barrel downward so that on the grades, it was about level. The engines went routinely from almost level to steeply upward and as a result the level of water over the crown sheet could change from perhaps as much as a foot to almost nothing at the summit when you leveled off. The water glasses were much longer than on a standard locomotive. There was always some concern that on the steepest grades, the front of the tubes would be uncovered and start leaking, but that rarely happened. The rule was to run three guages of water at all times on the grades and two guages on the flats. If you adhered to this, no ill effects.

>

wrj494@aol.com

I certainly wouldn't run it with the nose pointing downward. The water would be off the crown sheet then...boom!!!

I'm sure Dianne can correct anything I goof on or miss, but as I recall, the incline climb was one of the old JI Case adverising gimmicks where the Case dealers at various fairs would challenge the other makes to compete with them. It was a "rigged" contest in the sense that this was something Case engines did well, so the ramp was fine tuned to a Case engine's handling characteristics. ...just like AD Baker had his power eating fan (which worked best with the 36" dia flywheel diameter of the Baker engines, of course), or the obstacles at the Huber straddling demo.

The idea was to climb halfway up the ramp, stop, then continue, stop at the top to blow the whistle, and get ready to back down, stop miday again then finish, all without running out of steam or stopping on dead center. Most traction engines don't draft well at this angle, plus the dome needs to be mounted forward enough to get dry steam. And one other biggie, there needs to be enough mass ahead of the rear axle to keep the beast from rearing up. Often the Case dealers would even "cheat" further by removing the exhaust nozzle from the climb engine to reduce back pressure, and exhaust velocity.

Yes, I suppose that in theory you could overheat the front portion of the tubes, but they really aren't exposed more than a few minutes.