Two Rod and Valve Gear Questions

Tue Aug 7 10:05:28 EDT 2018

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

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: 

Good morning,

Here it is.

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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