List
After I made my post, late last night, I thought of a
few more comments about FWH's. First, some may not
know what we mean by thermal efficiency. In rough
terms it is the ratio of energy out of a system to
energy into a system expressed as a percentage. Thus,
when you increase the thermal efficiency of a
locomotive, each BTU produced in the firebox produces
more available drawbar horsepower. As an aside, you
can do the same thing by burning a better grade of
coal. Each pound of coal produces more drawbar
horsepower. That is how the fuel inspector at Valier
earned his keep.
FWH's had some other advantages, not mentioned. The
open systems deaerated the feedwater. This made better
heat transfer, and helped prevent foaming and
corrosion. It is said that FWH's also produced a more
uniform temperature in the feedwater, which reduced
thermal stresses in the boiler.
FHW's, on the Q, must have been a hard sell. With
on-line coal mines and oil wells, and with plentiful
water supplies (at least on Lines East), the cost
saving on these items would have been minimal! The
best pitch would have been, "you can get more work out
your existing motive power".
Lastly, there was some discussion about FWH's on
switch engines. In yard service, the advantages of
FHW's could not be fully realized because switch
engine seldom used all the horsepower they had.
Coalfield mine switchers were different. The old
Mikados were in a service, that today, we would call,
"road-switching. The Valier job had a long haul of 25
miles from Valier Mine to Centralia Yard. It was even
10 miles from the Royalton Mine to the North Yard at
Christopher!
John D. Mitchell, Jr.
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