Re-gauging a Bachmann Shay

Using the box the locomotive was delivered in, line it with a soft cloth and turn the locomotive upside down in the box. The soft cloth will reduce the chances of damaging the locomotive. Locate the bolster cross head screws (part number 10297) and using a small cross headed screw driver replace the trucks. At this point, I'd suggest modest lubrication (e.g. with Labelle gear oil or similar) of the drive shaft components.

Break in your locomotive by either running it on a short 3' test track or better still a good sized layout and varying its speed and direction. When you're happy with the locomotives performance, glue the four side frame covers back on with CA glue.

Ref. Figure 6.

Cut both brake beam ends as shown in Figure 6. It is necessary to cut the beams because the side frames are now 0.100" wider and cutting them allows the brake beams to fit. Glue them back onto the trucks with CA glue.

That final step completes the conversion. Now, where's that other Shay?

Final thoughts...

In my opinion, all of the other Bachmann On30 Shay re-gauging articles that I have read describe approaches that widen the trucks but mainly on the geared side e.g. 0.060" on the geared side and 0.040" on the non-geared side. The problem that I see with these other approaches is one of horizontal drive shaft alignment. Pushing out the trucks mostly on the geared side results in additional strain on the horizontal drive shaft universal joints. This in turn tends to result in poorer low speed performance, reduced reliability and noise.

One thing that I have noticed even with a stock Bachmann On30 Shay is the inability of the front truck to negotiate a moderately tight right-hand turn (when viewed from the cab, facing forwards). There's no question in my mind that the horizontal drive shaft components limit the locomotives ability to perform these turns. Widening the trucks on the geared side tends to worsen this problem and so, for both reasons this is why I have elected to widen my trucks mostly on the non-geared side.

Questions or comments? You can contact me at