Empty (tare) weight of 611's Auxiliary Tender?

Thu Jul 9 07:37:30 EDT 2015

Bud:

Thanks for sharing!

Dave Phelps

In a message dated 7/9/2015 3:51:49 A.M. Eastern Daylight Time,  
nw-mailing-list at nwhs.org writes:

Gentlemen,

The 611 is as good now as ever.

I have Bob Pilchers graph he plotted of the A, J and Y-6b’s which are  more 
detailed than I was able to reproduce in the Giant book.  The J  could 
develop a continuous 4500 DBHP or greater between 25 and 65 MPH with a  maximum 
of 5150 at 40 MPH.  His graph and curve show the J at 26 MPH  generating 
4575 DBHP.  You mentioned that the N&W was conservative –  yes and no.  
Pilcher, as Engineer of Tests for steam, wanted to show what  the locomotive could 
do day in and day out, not just what it could do under  ideal conditions.  
Also the railway wanted to know what the locomotive  could do at the drawbar 
and thus when you see the drawbar HP curves for the A  and Y-6b’s, they 
showed what they were capable of behind the A-tank.  The  curves for the J’s 
were computed before they were placed in freight service  using A-tanks during 
the last year of their revenue service and of course the  excursion service.

This latest testing shows that the 611 is as good now as ever which is a  
credit to those who designed and built her, and to those that prepared her 
for  present service.

Good job.

Bud Jeffries

From: _NW Mailing List via NW-Mailing-List_ 
(mailto:nw-mailing-list at nwhs.org)   
Sent: Wednesday, July 08, 2015 2:07 PM
To: _nw-mailing-list at nwhs.org_ (mailto:nw-mailing-list at nwhs.org)  
Cc: _NW Mailing List_ (mailto:nw-mailing-list at nwhs.org)  
Subject: Re: Empty (tare) weight of 611's Auxiliary  Tender?

Based on the information from Ken, below, and Dave Stephenson in his  
response, I calculate that the auxiliary tender required about 370 drawbar  
horsepower to be kept moving at 26 mph on the 1.34% grade.  This includes  the 
following assumptions:
- The "Modified Davis" train resistance formula gives a reasonable answer  
(it's sort of the "industry standard", so that should be safe...)
- The Auxiliary Tender was still full
- The measurement was on tangent track (this assumption is mandatory  since 
I had no information regarding specific location with respect to a  curve) 
OR the quoted grade was compensated.
- Yes, of course I added grade resistance to the rolling  resistance.

Added to the 4400 DBHP the NS Research Car is quoted as having measured,  
this compares favorably with the slightly over 4500 DBHP  in the N&W  curve 
reproduced in Col. Jeffries' book, and is just about on (as close as you  can 
read the curve) the curve Classic Trains published (on-line) in  
conjunction with their special issue on 4-8-4s.

Several relevant conclusions, in no particular order:
- There have for years been "whispered" thoughts that the N&W's  published 
capabilities for the J were...um...conservative.
- Spencer did a super job!
- "The Old Girl" hasn't lost a step!

Thanks to Ken and Dave for their assistance!

Dave Phelps

In a message dated 7/8/2015 1:41:37 P.M. Eastern Daylight Time,  
nw-mailing-list at nwhs.org writes:

Dave  

The best I can do is off NS' diagram sheet for the 250001 and 250002,  last 
updated was 1-22-1991, which states an average light weight of 143,650  
pounds.

Ken Miller

On Jul 8, 2015, at 10:31 AM, NW Mailing List via NW-Mailing-List  wrote:

Could some kind soul please provide the empty (tare) weight of 611's  
current auxiliary tender?

I need the information to complete the input data to calculate, using  the 
modified Davis train resistance formula, how much the addition of the  
auxiliary tender impacts the drawbar horsepower measurements reported from  the 
NS Research Car during the recent excursions.  Then, a valid  comparison can 
be made with the N&W curve reproduced in Col. Jeffries'  book, and the curve 
Classic Trains published (on-line) in conjunction with  their special issue 
on 4-8-4s.

Thanks in advance,

Dave  Phelps

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