Steam questions

NW Mailing List nw-mailing-list at nwhs.org
Wed Nov 11 15:52:18 EST 2009


One of the eastern railway museums has an 0-6-0 - I think it's at Monticello, Ill. - which has a boiler protruding into the cab but not all the way; its throttle is on top of the boiler like an M's but it has a rear facing linkage to a lever on the boiler backhead that goes to a rod extending through a packing gland like those on the K-2s, etc. Really a Rube Goldberg arrangement.

EdKing
---- NW Mailing List <nw-mailing-list at nwhs.org> wrote:

> Ed,

>

> Thanks for pointing out the other arrangement for the horizontal throttles.

> After I hit the send button I thought of the W's and M's with the firebox

> that extended so far back into the cab as to separate the engineer and

> fireman, and I realized that those throttles had to be ahead of the boiler

> backhead.

>

> Gordon Hamilton

>

> ----- Original Message -----

> From: "NW Mailing List" <nw-mailing-list at nwhs.org>

> To: "NW Mailing List" <nw-mailing-list at nwhs.org>

> Sent: Wednesday, November 11, 2009 11:35 AM

> Subject: Re: Steam questions

>

>

> > To expand on what Gordon Hamilton wrote about throttles -

> >

> > M's and W's and other engines whose cabs were mounted astraddle of the

> > firebox had their throttles on top of the boiler for convenient handling

> > by the engineer. These throttles operated a rod that went directly above

> > the top of the boiler into the back of the steam dome (through a packing

> > gland)where the actual throttle was located. The throttles described by

> > Mr. Hamilton were on the E-2s, K-2 and K-2as M-2s and subclasses and

> > earlier Mallets up through the Y-4s.

> >

> > EdKing

> > ---- NW Mailing List <nw-mailing-list at nwhs.org> 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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