Bachmann Shay Modeling Tips

It's hard to find anyone modeling narrow gauge in 1:20.3 scale that doesn't own a Bachmann Shay. I had the problem many have reported with the wheel bearings that fell apart. Bachmann replaced both trucks for me at no cost. I also had some problems with the contacts and installed the Hillside Railway replacement contacts. That solved the problem. Despite the problems, my Shay has been my best running engine. It pulls well on my 4% grades, it will run when the track is too dirty for most of my engines, and it is my least likely engine to derail. For all kinds of useful tips on the Shay, check our George Schreyer's  Technical Tips page.


Fixing a Bind in the Cylinder Assembly

After owning my Shay for nearly two years, a new problem developed: something in the cylinder mechanism was binding and the engine would not move. Removing the cylinder assembly, I soon discovered the problem. The frame of the Shay is a metal I-beam. Apparently after much running, a component of the valve gear on each cylinder can come into contact with the I-beam. This valve gear component rocks up and down as the engine moves. If it slides under the lip of the I-beam, the lip of the I-beam can prevent it from rocking as it should. This had happened at some point with enough force on my Shay to actually bend the valve gear component. While the cylinder assembly was out of my Shay, I took a picture of the front cylinder and marked the corner of the valve gear mechanism that can bind against the I-beam. 
In the photo with the cylinders removed, you can see the wear in the I-beam where the valve gear has been rubbing (Sorry; this one is a little fuzzy.) To remove the cylinder assembly, remove the two screws between the cylinders and a third screw that goes through a slot into the bottom of the frame. Open the bottom of the firebox and turn the two plastic locks to the correct position with pliers. You may have to loosen the screws holding the locks a tiny bit. Now you can wiggle the assembly loose.
I filled the space between the lips of the I-beam with styrene at the trouble points. I also glued a very thin piece of styrene over the top lip of the I-beam in the two worst problem areas. I used a couple of the thin shims that come with Kadee couplers for this. In the final photo, the styrene has been glued in and painted engine black. This area is almost invisible once the cylinder assembly is reinstalled. After the repair was completed, the Shay ran smoothly at all speeds and in both directions without any hint of click or hesitation.

Copyright 2004 Donald Nute

These pages last modified: 2/9/2004.

Please send comments to: donald@nute.ws.