Re: NNG- but big steam

I did some searching today out of curiosity and located a builders drawing of the class...was quite surprised to note that 1309 has a combustion chamber.
Not just a combustion chamber, but one that is 90" deep. That's huge. Compare to Southern Pacific AC-7 (Cab-Forward) with 68", F-3 (2-10-2) with 64",
GS-3 and later with 80". Even the long barreled SP-1 through 3 (4-10-2) were 74". Almost makes me wonder if this is a typo?
Was this feature in the earlier 2-6-6-2s?

When you compare superheating surface, the C&O mallet has a modest 975 Sq. ft. whereas all of the previously mentioned SP engines have more.
The AC-7 has fully 3 times the area with 2988 Sq. ft. I'm a little surprised that 1309 superheat surface isn't more, especially since the steam is used twice
and is down in temp by the time it is admitted to the L.P. cylinders.

The other thing that caught my eye is that weight on the drivers is substantial, so much so that the factor of adhesion is up around 4.6 or better.
This locomotive should be a pulling fool.



Edited 2 time(s). Last edit at 01/14/2017 09:20AM by Tom Moungovan.