# 1:20.3 Bachmann 3-truck Shay Curve Negotiation



## JunctionJoe (Sep 2, 2013)

My first post on mLS.com- here goes. I am having a 11' x 11' expanded oval ceiling layout crafted and was informed by the designer that my intended locomotive purchase, a Bachmann Spectrum 3-truck 1:20.3 Shay, would not make the 5' diameter curves. The roadbed hangers are 15" length as they hang from the ceiling and each is 12" wide. The hangers looked to be spaced approximately 16" apart from the inner-most point in curve. Can anyone tell me if it the reason he's saying 'nay' to the Shay is because of the hanger spacing vs. locomotive length or is the Shay's drive train an issue in a 5' diameter curve? 

Appreciate any advice. I am prepared to go with a Bachmann Spectrum two-truck Climax if need be but there are some pretty sweet deals on DCC sound onboard Shay locomotives right now.


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## Curmudgeon (Jan 11, 2008)

From the Bachmann website: 
"This model performs best on 8' diameter curves or greater." 

There is a reason there are sweet deals on Quasinami equipped three truck Shays. 
Best bet it to choose the system you want to use, buy a non-Quasinami equipped unit, and install away....or, if really cheap, you can buy one ready-equipped and fix it later. 

I had one early on. Due to circumstances...it is now just like my other three truck Shay. 

Mine would not reverse. Headlight would, but it only ran one way on track power. Had to flip the polarity switch, then it only ran that way. 
Reversing the gray and orange motor leads fixed that for track power...which it should not have done. 
Full power test for current, voltage, and drawbar pull resulted in an on/off/on/off/on/off situation with lights flashing...using a power supply checked with Soundtraxx would work and cause no damage. 
Sent the unit back to Soundtraxx...OEM...they had no data on it...I had to tell them how to connect it...they had no way to fix it as all the data went to the OEM supplier....so it's landfill in Durango. 

Experience. 

Your mileage may vary. 

TOC


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## Dwight Ennis (Jan 2, 2008)

The Bachmann Shay (or just about any Shay for that matter), will negotiate tighter curves if the cylinders and drive line are on the outside of the curve. Mine (original Bachmann two-truck Shay) would happily go around R1 (4 ft. dia.) curves with the cylinders/drive line on the outside. Not so if they were on the inside. The reason is that there's limited travel of the square sliding junction in the drive line between the trucks and the cylinders. If the curve is too tight, the square junction reaches the limit of it's compression travel and binds, limiting how far the truck can swivel. 

Since you intend to operate on an oval near the ceiling, I'm sure you don't want all that nice moving mechanical drive line stuff to be facing the wall where it can't be seen. Best bet is to have someone who still has a Shay to try it on R2 (5 ft. dia.) curves with the cylinders/drive line on the inside of the curve and see if it will take it. It seems to me mine would take an R2 curve in either direction, but it's been 10 years and my memory could be off.


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## JunctionJoe (Sep 2, 2013)

Dwight, thank you for sharing your experience. Makes perfect sense. I've decided that the two-truck Climax will be the pull power on this railroad.


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## JunctionJoe (Sep 2, 2013)

Dwight, I took your advice to heart, gambled and made a later purchase of a Bachmann Fn3 model 82697 w/DCC and Tsunami Soundtraxx. I put the drive line outboard and watched her go around my R2 curves beautifully! Here's a video of the results . . . http://www.youtube.com/watch?v=pcgPoYYCdaY.

Thank you for the accurate information. 

Joe W.
Windsor, VA


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