There are 3 saved SP class c-8 2-8-0s but all are missing the eccentric blades and pistons which were removed by the SP when they transported the engines to the display sights. The 2706 John Manley is trying to restore is being enclosed in a repair shop in Colusa, CA. It has the eccentrics but they are of unusual construction in that they look like flat belt pulleys with flanges on both sides. We are trying to get any information on the valve gear, valve settings and eccentric blade designs used on this class of locomotive so that the missing parts can be made. That information will also be useful to the other two engines, 2720 at Compo and the 2718 at Alturis.
The C-10 #2852 in Orland, CA is complete but does it have the same valve gear?

Any help will be appreciated.

I read that the SP's 3' gauge #9 had the same eccentric design as in the bottom photo.

The story goes like this:

When the SP's "Laws to Keeler" branch was on its last days, the "flange" wore off of one side of its eccentric (the flanges in your photo) and the eccentric blade fell off the eccentric and down onto the driver axle, and thats what stopped the last of the SP 3' 4-6-0's in CA.

Morning Dave. I'm no expert on the SP consolidations, but that is, from the looks of it, your standard stephenson link motion. Some of the photos of inside-cylinder engines under restoration in the UK that I've seen have those same ports, which were used apply lubricant the motion through connection to a lubricator (the most common that I've noted is the Wakefield design) with flexible hoses.

Hi Dave

I found a drawing of a Stephenson Valve Gear , on http://www.steamlocomotive.com/valvegears . The site does have some information dealing with the valve gear . I hope the drawing will be of some sort of help. Pat

Oh boy....in general terms, the straps either have flanges on them or the eccentrics have flanges on them, but of there are flanges on both it would act as a bearing labyrinth and help keep dirt out. So, you have interesting options here......as well as choices about bearing materials, lubrication systems and lubricants......have some fun with it.

Stephenson gear is not hard to understand and there's a LOT of open sourced information available on the web. Live steamers are another great source, just make the parts bigger. You won;t have much troubnle working backwards from the basic dimensions of the locomotive to figure out what the original specs would be....or at least near enough to do the job just fine.

It wouldn't hurt to work through the archivist at CSRM to see what (if any) of the original drawings and specs are available for this class. There's a lot out there if you ask the right people, and they are the most logical repository to start with.

Don't worry about setting the valves for now - it's easy on Stephenson: just make sure the valve is open by the designed amount of lead required on both ends in both gears at both dead centers. If not quite, split the difference in the variation if you run equally in both directions, or compromise with reverse and make forward right if you run forward always.

dave

To the best of my recollection, the eccentrics on SD&A 104 (SP 2720) don't look like the ones in the posted photo of 2706. I'll be out at Campo this weekend, and, if I have time, will try to get a couple of photos. (Teaching an all day long class for new brakemen). I do know that the eccentric rods have been removed, but I think we have them. Might take a while to dig them out for photos.

Jim Baker, PSRM, Campo, CA

Stephenson valve motion was kind of generic, so many locomotives used it prior to 1900 and after, and that included such "odd" locomotives as Shays, including the last one, built in 1945 (WM 6, now in operation at Cass Scenic Railroad in West Virginia).

http://limalocomotiveworks.com/WM_Shay_6-RS.JPG

http://www.gearedsteam.com/shay/wm6.gif

http://farm2.staticflickr.com/1106/5115 ... 8f78_z.jpg

http://www.steamlocomotive.info/vlocomo ... splay=1358

Equally important to note is that the Southern Pacific, Union Pacific, Illinois Central, and some other roads in that time period were under common management, and shared a design bureau. Quite a few Union Pacific sisters are still around, and one is (or has been) in operation in recent years--No. 618, on the Heber Creeper in Utah:

http://en.wikipedia.org/wiki/File:Heber_UP618.JPG

http://www.yesteryeardepot.com/SP2724.JPG

http://steamlocomotive.com/consolidatio ... =up#photos

In key dimensions, the two locomotives are amazingly close; it wouldn't surprise me if parts were interchangeable:

http://www.steamlocomotive.info/vlocomo ... isplay=216

http://www.steamlocomotive.info/vlocomo ... splay=1204

Might want to check with the Heber people, and see what they might have to say.

And yes, the valve gear under the C-10 2852 is very close to what you should have.

.

SteamerDave: Well, I guess my memory isn't as good as I thought. Friday I climbed up over the drivers of SD&A 104 (SP 2720) to take a photo of the eccentrics. No eccentrics on the axles! I poked around in our storage area a bit, and found the eccentrics: just like the ones in your photo of 2706. I didn't have too much time, but did look around some more, but could not find the eccentric straps or rods. That doesn't necessarily mean they aren't there, though. Lots of parts from all of the five steam engines we have, all piled up in no particular order. Then there's the other storage area.......

Sorry I couldn't have been of help.

In looking at Tim miller's photos of the 2720, there are two very interesting things.

1. The left cylinder is apparently the original cylinder WITH THE ADDED adapter to convert it to an outside delivery steam pipe. The NP 2156 at the MTM Jackson street roundhouse in St. Paul has inside steam passages to the valve like your engine had originally BUT. the inside passage broke out from freezing while in the zoo for many years. Our plan is to convert to outside admission steam pipe as your engine has. I have asked Tim to really check over the left cylinder on your engine. I strongly suspect that the inside passage it originally had is now blanked and I would like to know how the SP did it. If the SP did it, we can do it.

For the rest of you RYPN ers out there, do you have any further examples of such a conversion. The hardest part will be to blank off the original steam passage.

2. We will need at some point to measure your pistons and piston rods. since yours is the only c-8 with them.