Anybody know why Young valve gear wasn't used more extensively? I've read some glowing reports about it, but it seems like it was only used on the UP, and even then only sporadically. In the 1938 Locomotive Cyclopedia, the Pilliod Company (the folks that brought you the Baker valve gear) was advertising Young valve gear. Did they by the rights to the design? Do any of the Pilliod Company records still exist? Any insight would be appreciated.
-Chris

UP used the Young valve gear I know on the 7000 Mountain type passenger engines & the 5500 series 2-10-2 of which 5511 is the only survivor. UP had many many problems with the 7000 series which were built by ALCO to UP specs & were built way to light weight for what was expected. ALCO was on sight several times with recomedations & ideas but they never lived up to what was expected of them. In all fairness not all the problems were with the valve gear though.........................Wooly

The Museum of Transport in St. Louis has the frame, cylinders, wheels and valve gear of a Terminal Railroad Association 0-6-0 which was one of a class that had Young valve gear. This artifact is the only example of Young valve gear that I have ever seen. I remember seeing these engines working around Union Station.

One use for the Young gear was for retrofiting locomotives that had worn out Stephenson gear inside the frames to an outside valvegear that was easier to maintain. The Young gear required minimal modification since it did not use eccentric cranks.

It is my understanding that the Baker and Young valve motions had very similar characteristics, i.e. a long valve motion (Baker had several choices for length of valve motion.). The Baker had a very great advantage in that it didn't utilize a sliding link block most common valve motions used for variable cutoff but was based on pivots using pins and bushings. (I've read that the last five N&W "A's" used roller bearing even on the Baker valve motion.) The only place that it could really go out of time was a slipping eccentric. Because of it's mechanical simplicity, it was comparatively light weight thus requiring less horsepower to operate. Baker use was quite wide spread, N&W using nothing but Baker motion and it can even be found on many of the Sandy River & Rangley Lakes two footers.

On the other hand, the Young valve motion had many links, two sliding blocks and three cross frame shafts (one variant used concentric shafts) to transmit motion across the engine. Each of those shafts had radius arms at the end to translate the reciprocal to rotary motion then back to reciprocal motion on the other side of the engine. Each of those arms were clamped to the shaft and became a potential spot to lose timing not to mention torque issues on each of the shafts. The Young valve motion appears to considerably heavier than any of the other common valve motions and as a result would require more horse power to operate and provided many more opportunities to go out of time. And I'm sure timing was harder to set because of using the cross head on the other side of the engine for motion. Assuming both motions had nearly equivalent benefits, it would appear that the simplicity of the Baker would displace the Young except in very particular circumstances.

Ed

One application where Young valve gear was used almost exclusively was with duplex steam pumps, such as the one shown above. Steam pumps had their cylinders close together, and did not need to be reversed, nor need variable cutoff.

In this application, you have a fairly short pair of shafts with a lever on end and a crank on the other. You have a connecting link between the crank and the valve stem, and that's it. Adjusting the timing is matter of moving the piston rods so that when one is in the middle, the other is at the end of it's stroke.

-James Hefner
Hebrews 10:20a


Surviving World Steam Project