two questions about steam

[nw-mailing-list at nwhs.org]

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.
 
The second question relates to the locomotive weights given in one of the appendices to Jefferies' "Giant of Steam".  Total weight of the Y6b including tender is listed as 990,100 lbs, and 611,520 lbs without tender.  So tender alone would be 378,580 lbs.  22,000 gallons of water weighing 8.33 lbs/gallon would weigh 183,260 lbs, and adding 30 tons of coal would make the total load 243,260 lbs.  This would make the empty weight of the tender 135,320 lbs, over 67 tons, which seems very heavy, since I don't see how any mechanical advantage could be gained by adding weight to the tender.
 
Thanks in advance for your ideas.
 
Tom Leuthner
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://six.pairlist.net/pipermail/nw-mailing-list/attachments/20060225/8b522ff7/attachment-0001.html