Tom Moungovan Wrote:
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> guymonmd Wrote:
> --------------------------------------------------
> -----
> > When the locomotives were converted from 2-6-6-2
> T
> > to 2-6-6-2 for Sumpter, I would guess there was
> a
> > loss of TE due to the loss of the weight on the
> > drivers.
> > Does any one know how much TE was lost?
> > Since the weight of the water tanks on the
> engine
> > varied depending on how much water was in them,
> > there may not be a definitive answer.
>
> Actually, there should have been no loss of t.e.
> at all as it is a function
> of cylinder volume, boiler pressure and driver
> diameter.
>
> Any loss or gain of weight on the drivers would
> however, have a direct
> influence on factor of adhesion.
Correct. A often overlooked detail of tank engines is that they were generally designed to have the ideal factor of adhesion of 4.0 when the tanks were empty. In looking at the Baldwin magazine article, the F of A with full side and fuel tanks was 4.62 (42,100 TE / 194,500 weight on drivers). Subtract the weight of 2,800 gallons of water, and 9,000 lb. of coal, and you are left with 167,867 WOD. 42,100 / 167,867 = 3.99 F of A, theoretically still good to pull maximum tonnage, though how you are going to do that with no coal or water is beyond me.
The material from SVRy says that the WOD was rated at 182,000, almost exactly half way between the full and empty weights as tank engines, so the extra thick running boards compensated for the weight of the empty tanks themselves, and some of the water.