Steam questions

[NW Mailing List]

I have a question!   In regards to the Y5's with a Bradford Front End  
throttle, why was it there and not in the steam dome? Did it provide a  
shorter path to the front engine when in Simple?

MArk Lindsey
Stuck in the 1930's

On Nov 11, 2009, at 10:39 AM, NW Mailing List wrote:

Nathan,

In addition to what others have furnished on the two types of throttle  
levers on N&W steam locos, a few more comments  may help.

Older N&W steam locos used the "horizontal" throttle levers, which  
were pivoted to the left (toward the fireman) of the vertical  
centerline of the boiler and which were pinned to a rod (or stem) that  
typically passed through a stuffing box on the boiler backhead on the  
vertical centerline of the boiler and above the crown sheet.  This rod  
reached through the boiler to a bell crank under the steam dome, and  
the other arm of the bell crank raised or lowered the throttle valve  
when the rod from the throttle lever in the cab moved forward or  
backwards, respectively.  I can think of two problems with this  
throttle arrangement.  One, the sliding action of the rod in the  
stuffing box on the backhead probably caused more wear on the packing  
than the rotary action of the shaft in the stuffing box leading to a  
dome-mounted throttle operated by the outside throttle linkage (and a  
vertical throttle).  Two, with the throttle lever in the "off"  
position, expansion and contraction of the boiler might be different  
than the expansion and contraction of the rod through the boiler  
raising the throttle valve just enough to leak steam to the cylinders,  
which could cause the locomotive to "walk away."  This happened at  
times.  The more modern arrangement of the outside linkage associated  
with vertical throttle levers largely avoided this problem by  
incorporating a rocker lever mid way between the throttle lever and  
the throttle valve to provide compensation for the expansion and  
contraction of the boiler.

Gordon Hamilton

----- Original Message ----- From: "NW Mailing List" <nw-mailing-list at nwhs.org 
 >
To: "NWHS" <nw-mailing-list at nwhs.org>
Sent: Sunday, November 08, 2009 12:33 AM
Subject: Steam questions



> Alright gang I'm back with more questions, Both are for the most part

> quick and hopefully simple. First what orientation did N&W prefer for

> the throttles of their steam locomotives? Horizontal or Vertical? I

> think the J and A both had Vertical oriented but I am not sure if that

> was N&W preference of just what they used on those locomotives for  

> some

> reason.

>

> Second Question is a little harder but I feel it will be easy for

> someone to answer. In listening to Link's recording of  Y6 working

> Waynesboro, at time I hear a distinct "thump thump thump" that is

> rythimic then it quits then it does it again. It does not sound like a

> Cross Compound to me so I am buffaloed as to what it is, Feedwater  

> pump

> perhaps? I head the same sound in Hooters on Blues ridge when there  

> is a

> Y doing Switching at Blue Ridge. It happens while the locomotive is

> still moving but the throttle seems to be closed and the engine  

> coasting.

>

> Thanks ahead of time,

> Nathan

>

> -- 

> Nathan Simmons

> trainman51 at gmail.com

> http://www.t-51.org

> KI4MSK

>

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