Challengers and coal

[NW Modeling List]

I assume that a double stack ( 2 blast pipes) would have a smaller nozzle in the blast pipe. These 2 nozzles would have an aggregate area equal to that of a single stack loco of similar characteristics.

Also, on a Mallet simple I suppose 2 blast pipes allow for a different nozzle for the front and  rear cylinders to optimise the draught and thus power obtained from the loco.

Barry Reeves
Songwriter & Musician
www.northwestlondonblues.co.uk





Date: Thu, 25 Feb 2010 06:22:31 +0000
Subject: Re: Challengers and coal
To: nw-modeling-list at nwhs.org
From: nw-modeling-list at nwhs.org

A couple of interesting replies on drafting. Regarding twin vs singlestack, my intuition told me that the double stacks would create less draft because of the same volume of steam being exhausted through the larger surface area that I would assume two nozzles would have (all else being equal). Why is this assumption apparently wrong?
( though  the reason why the UP coal would need a higher firing rate (and therefore, draft) now makes sense) 
Matt

On Feb 24, 2010, at 5:09 PM, NW Modeling List <nw-modeling-list at nwhs.org> wrote:


The proportions of 'burnable carbon' and inert material vary considerably depending on the source of the coal.


The UP needed a higher firing rate with their lower quality coal to attain performance.  In general; UP coal


would produce more ash; require more air; and increase build-up in the hot side of the boiler tubes and flues.


With better coal, the Clinchfield was able to maintain draft with a single stack.


 


Jerome Crosson.










-----Original Message-----

From: NW Modeling List <nw-modeling-list at nwhs.org>

To: NW Modeling List <nw-modeling-list at nwhs.org>

Sent: Wed, Feb 24, 2010 12:12 pm

Subject: Re: Challengers and coal











Not to sound stupid but what would be a "better" coal to use? Isn't the majority  

of coal deposits in the US  bituminous coal? 

 

Thanks 

Jon Kelley 

 

Sent on the Sprint® Now Network from my BlackBerry® 

 

-----Original Message----- 

From: NW Modeling List <nw-modeling-list at nwhs.org> 

Date: Wed, 24 Feb 2010 11:41:15  

To: 'NW Modeling List'<nw-modeling-list at nwhs.org> 

Subject: RE: Challengers and coal 

 

Maybe related and maybe not, but the Clinchfield did change the way the UP  

Challengers were drafted (i.e., single stack replacing double stack)    Jim  

Nichols 

 

I would guess 


> that better coal would make the Challenger steam easier. 



> The implication is 



> that it would increase the effective output. (as opposed to 



> theoretical 



> output)      Jim 



> Nichols 


=============== 

 

Trying to keep this on the lite side, I believe the Challengers Clinchfield got  

from D&RGW were of the same design as the last UP Challengers, so they must have  

run on some decent coal on CRR. ;-) 

 

Mark Peele 

Catonsville, MD 

 

 

 

 

       

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