Two Rod and Valve Gear Questions

Tue Aug 7 12:18:25 EDT 2018

Re Garratts
Many years ago I entered the NWHS Convention art class with a watercolour
and modified photo of what an N&W 2-8-2 2-8-2 Garratt might look like.
Unfortunately the artwork has disappeared over time.  Around the same time
there was quite a discussion on the Mailing List on the advantages and
disadvantages of Garratts versus Mallets and why they were never used in
the US.
Regards,
Richard Hood
West Dorset
England

On Tue, 7 Aug 2018, 15:42 NW Mailing List via NW-Mailing-List, <
nw-mailing-list at nwhs.org> wrote:

> Thanks for the e-mail. It is a 2-6-2+2-6-2.
>
>
>
> I hope we can get this all to work.
>
>
>
> Regards
>
>
>
> Phil
>
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>
>
>
>
> *From:* NW-Mailing-List [mailto:nw-mailing-list-bounces at nwhs.org] *On
> Behalf Of *NW Mailing List via NW-Mailing-List
> *Sent:* Tuesday, August 7, 2018 1:24 PM
> *To:* NW Mailing List via NW-Mailing-List
> *Cc:* NW Mailing List
> *Subject:* Re: RE: RE: RE: Two Rod and Valve Gear Questions
>
>
>
> Wow! Gorgeous machine. Is it a 2-8-2+2-8-2? Best of luck with the project.
>
>
>
> Roger Huber
>
> Deer Creek Locomotive Works
>
>
>
>
>
> On Tuesday, August 7, 2018, 5:42:34 AM CDT, NW Mailing List via
> NW-Mailing-List <nw-mailing-list at nwhs.org> wrote:
>
>
>
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>
> Good morning,
>
>
>
> Here it is.
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>
> It has fallen on hard times since this picture was taken. The loco was
> effectively abandoned so we stepped in and acquired it for the price of a
> second hand car. At present it is at the Sandstone Estate. We are thinking
> of a cosmetic re-build and then getting it back to the UK. Beyond this the
> developing plan is to go for a new build NGG17 incorporating all of the
> bells and whistles from 141 plus a load more advanced steam technology.
> Ambitious? Certainly. Worth doing. Of course.
>
>
>
> Regards
>
>
>
> Phil Mortimer
>
>
>
> *From:* NW-Mailing-List [mailto:nw-mailing-list-bounces at nwhs.org] *On
> Behalf Of *NW Mailing List via NW-Mailing-List
> *Sent:* Monday, August 6, 2018 9:18 PM
> *To:* NW Mailing List via NW-Mailing-List
> *Cc:* NW Mailing List
> *Subject:* Re: RE: RE: Two Rod and Valve Gear Questions
>
>
>
> The Red Devil is awesome! A Beyer with similar mods has to be something to
> see!
>
>
>
> Roger Huber
>
> Deer Creek Locomotive Works
>
>
>
>
>
> On Monday, August 6, 2018, 2:01:10 PM CDT, NW Mailing List via
> NW-Mailing-List <nw-mailing-list at nwhs.org> wrote:
>
>
>
>
>
> Touché!
>
>
>
> The book by Andre Chapelon (La locomotive a Vapeur) delves into all of
> this. Ditto the book by David Wardale on the re-built 4-8-4 (Aka The Red
> Devil) in South Africa in the 1980s. This looked at the whole
> fuel/steam/gas flow plus modifications to the air admission to the firebox
> together with steam admission to prevent ash fusion. The nozzle used a
> modified Kylchap/Porta which is very efficient at entraining gases through
> the tubes. The whole valve gear bearing position was also probed together
> with a series of mods to the cylinders to minimise heat losses.
>
>
>
> The Red Devil is now back in action after a long period of dormancy. A
> small Garrett loco was also modified in South Africa incorporating a lot of
> the Red Devil modifications. (I own it!)
>
>
>
> Regards
>
>
>
> Phil Mortimer
>
>
>
> *From:* NW-Mailing-List [mailto:nw-mailing-list-bounces at nwhs.org] *On
> Behalf Of *NW Mailing List via NW-Mailing-List
> *Sent:* Monday, August 6, 2018 4:52 PM
> *To:* NW Mailing List via NW-Mailing-List
> *Cc:* NW Mailing List
> *Subject:* Re: RE: Two Rod and Valve Gear Questions
>
>
>
> There were many other factors involved in an engine being a rough rider,
> etc than having drivers quartered or at 120*. The springing had a lot to
> do, driver wheelbase and lead and trailing truck length and centering
> devices. It was an extremely complex process and often was trial by error
> to get the best for that engine or type.
>
>
>
> Just like draft depended on grates, firebox vs flue rations, stack height,
> taper & diameter and especially the nozzle. Many roads spent a lot of
> effort working on nozzle design. I read someplace the K-1 had some issues
> with draft when first released from Roanoke and they put a lot of effort
> into the nozzle and stack area.
>
>
>
> Roger Huber
>
> Deer Creek Locomotive Works
>
>
>
>
>
> On Monday, August 6, 2018, 9:36:22 AM CDT, NW Mailing List via
> NW-Mailing-List <nw-mailing-list at nwhs.org> wrote:
>
>
>
>
>
> This was also an area for dabbling by various steam loco engineers and
> designers in the UK.
>
>
>
> Most UK  2-cylinder locos were at 90 or 120 degrees. How much real
> difference this made in reality (fuel economy, maintenance etc.) is
> difficult to determine. Late series Britannia Pacifics were always deemed
> to be rough riding. By the same token some multi-cylinder locos were just
> as rough (Royal Scot 7Ps, Peppercorn A1s etc.) whilst others rode very
> smoothly. The A4 Mallard type was always deemed to be a very smooth running
> loco design with three cylinders a derived/conjugated valve gear for the
> inside cylinder.
>
>
>
> Regards
>
>
>
> Phil Mortimer
>
>
>
> *From:* NW-Mailing-List [mailto:nw-mailing-list-bounces at nwhs.org] *On
> Behalf Of *NW Mailing List
> *Sent:* Monday, August 6, 2018 1:44 PM
> *To:* NW Mailing List
> *Subject:* Re: Two Rod and Valve Gear Questions
>
>
>
> The ratio between the distance of the main pin from the axle center varied
> from engine design to engine design.  It would be different from, say, the
> Y-6 and the J – both engines had 32-inch strokes but a foot difference in
> driver diameters (assuming new tires).
>
>
>
> The normal practice in American railroading was right-hand lead.  The PRR
> was the notable exception to this; they used left-hand lead.  It was known
> that the side that had the lead pounded the track more than the other; one
> theory has it that PRR wanted the left-hand side to pound the roadbed
> harder because ot a preponderance of multiple-track railroading; the left
> side of the roadbed would be stronger.  The quarter was the standard for
> two-cylinder locomotives, assuring the most even distribution of torque
> during the rotation of the wheel.  Three-cylinder locomotives typically
> used a 120-degree ratio instead of a quarter.  The exception to this is the
> Baldwin 60000 three-cylinder 4-10-2 displayed at the Franklin Institute in
> Philly.  It’s drivers are quartered, but the third cylinder is 135 degrees
> from both the outer crankpins.
>
>
>
> Hope this helps.
>
>
>
> EdKing
>
>
>
>
>
> *From:* NW Mailing List
>
> *Sent:* Monday, August 06, 2018 6:16 AM
>
> *To:* N&W Mailing List
>
> *Subject:* Two Rod and Valve Gear Questions
>
>
>
>
>
> Hopefully there will be some talent left around which can give an answer
> to these two humble little questions...
>
>
>
> (1)  Is there always a mathematical ratio of 2:1 between (a) the distance
> from center of axle to center of main driving crank pin, on the one hand,
> and (b) the length of the stroke of the piston, on the other hand?  (Prima
> facie, this sounds like a really, really dumb question... sorry.)
>
>
>
> (2)  In quartering drivers on axles, how far in degrees is one driver
> advanced beyond perfect quarter, to insure that the engine will never be
> caught on dead-center?  (And I believe N&W used right-hand lead, contrary
> to most American practice, did they not?  If so, I wonder where that
> practice came from?)
>
>
>
> --  abram burnett,
>
> (who should probably just stick to turnip farming...)
>
>
> ===========================================
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