Coal size-

nw-mailing-list at nw-mailing-list at
Fri Mar 3 20:36:31 EST 2006

Also note that the advertising in the Locomotive Cyclopedia books (not
the little reprints but the big, old ones) describes the performance of
stokers which generally cite how the units crushed the coal for
distribution in the firebox itself by whatever the mechanical or
steam-blown means were used.

It was important to not have the coal too large as a good, thin fire
could not be made to sit over the grates and burn evenly and to not make
fines or dust as these could be drawn up by the draft and blown out
through the fire tubes. They could be not combusted or not combusted in
the right place for useful heat generation and heat transfer.

Also, a lot of fine coal or dust would get whipped out of the tender to
fall back on to the passengers in passenger trains. Not desirable!
Large lumps that could be broken up in the stoker made happier

G Rolih

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Sent: Friday, March 03, 2006 7:27 AM
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Subject: Re: two questions about steam

The 1947 coal size study was found by Louis Newton at
the archives (he has a phenominal memory). He pointed
it out to me at one of the sessions, and I'm currently
getting the data tables into spreadsheet format. Hope
to do an article in a future Arrow.

Dave Stephenson

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