Alco 3rd Cylinder Valve Linkage

[Mark Landgraf]

Hi

I was hoping someone might have a diagram showing how the external valve levers actuated the third cylinder spool valve. A couple of forked shafts, with offset pivot points, are fed from the extended front ends of the normal spool piston valve shafts.

Mark Landgraf
Albany NY

[Soot n' Cinders]

Sounds like what you're describing is Gresley conjugated valve gear. I don't know much about it but there are plenty of sources out there for it.

[Berkman]

That will be a massively complicated project to build a working 3 cylinder with conjugated VG in 7.5 gauge. I can't imagine dealing with the packing nuts and such on the middle cylinder

[Mark Landgraf]

Actually I've been scanning thousands of Alco builders photos for Alco Historic Photo. I've scanned several dozen images of the fronts of 3 cylinder locos in both standard and narrow gage. Unfortunately, they have all been from tri-pod level. I've been hoping for an overhead angle that better show it's movement relationships. Now, knowing what it's called, research will be easier.
Thanks
Mark

[Mark Landgraf]

Evidently the the guys at the factory got tasked with building a proof of concept working model. It appears to be about 3" scale. They appeared to be also testing the center siderod vs axle clearence.

It has nice cut aways so as to be able to see the movement. Knowing it was Gresley made finding it it Wikipedia a lot easier.
Thanks Mark

[SPSteam2491]

I found this video a couple months back from a gentleman in Japan building a 5" gauge locomotive with Gresley conjugated valve gear. It is really cool to watch the parts go back and forth.
https://www.youtube.com/watch?v=ATU24iu ... LL&index=5

He also has a description on his website for building the valve gear. The machining work completed so far has been outstanding!
http://livesteam.sakura.ne.jp/C53_201805e.htm

[SZuiderveen]

Curly Lawrence’s version of LNER V-2 2-6-2 “Green Arrow” from English Mechanics in 1936, 2-1/2” gauge. Take it for what it’s worth, it’s LBSC!

Steve

[davidk]

Hi Mark,

You might also find interesting the Wikipedia page for Gresley conjugated valve gear and Holcroft conjugated valve gear:
https://en.wikipedia.org/wiki/Gresley_c ... valve_gear
https://en.wikipedia.org/wiki/Holcroft_ ... y%20(SECR).

Harold Holcroft's patented design actually predated Gresley's version. Holcroft also contributed greatly to the design of the Gresley conjugated valve gear.

Harold Holcroft apparently was a close friend of LBSC, and helped him with conjugated valve gear for the Baker valve gear on his 2 1/2" gauge 4-cylinder Tugboat Annie design.

The late Don Ashton also has a section on his website, covering multi-cylinder designs:
http://www.donashton.co.uk/html/more_cylinders.html

David

[Jim_Nolan]

I might be able to help in the near future. I am researching Gresley's conjugated valve gear for a friend, in the National Railway Museum in York. I have a list of possible drawings that may be useful just waiting for the NRM to get back to work after Christmas.

[Mountaineer]

Suggest the OP seek a copy of Don Young’s design of the LNER Gresley A1/A3. He called his design Doncaster. FlyingScotsman is the preserved example of this class. His drawings are available from Reeves in the UK, and were also published in his magazine Locomotives Large and Small.

Mountaineer

[Mark Landgraf]

thank you for your assistance

Mark

[James Powell]

It certainly _can_ be done in 7.x, given we had a 2.5" gauge V2 with 3 cylinders- though I think dad gave up on it as watchmaking, and traded it for the 2-8-4 in 2.5"