two questions about steam

[nw-mailing-list at nwhs.org]

N&W was apparently very interested in the operating
economies gained by using various grades and sizes of
coal.  There was a series of tests run in Sept. and
Oct. 1947 with #2145.  Three sizes of coal were used:

2" x 0" (lots of fines)
2" x 1/4"
2-1/2' x 1/1/4" (almost no fines)

During road tests the advantage of sized coal was
about 14% over coal with large amounts of fines
(measured in lbs of steam per lb of coal).  Whether
N&W always used this size grading for coal I don't
know, but in photos the tenders look like they are
full of golf balls rather than dust and chunks.

Keep in mind the stoker screw will contribute a
certain of crushing regardless of initial coal size.

Dave Stephenson



--- nw-mailing-list at nwhs.org wrote:


> Hi Guys,

>  

> Have a question about the grade or size of coal

> pieces used in engines equipped with automatic

> stokers like the Y, A, and J.  The reason I'm asking

> is that I'm trying to convince a certain brass

> designer/importer of O scale models that his

> simulated coal loads are incorrect (other than that,

> the one model of his I own is great).   On my Y6a,

> the coal chunks look to be a good six scale inches

> across.  My limited understanding is that high

> pressure air was used to distribute the coal across

> the firebox.  Pieces 6" across just couldn't be

> propelled by air.  Pictures I've seen show a much

> finer grade.

>  



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