I’m taking a guess but I have an older Bachmann HO scale SD-40-2 six axle locomotive. (It has 5 fan vents on top. ) I cut off the coupler pockets since installing the standard Kadee no 5 couplers rode too low. Then on some occasions, freight cars toppled over due to a short coupler?-is this because the couplers installed were too short?
Should the couplers be mounted on the trucks or on the engine body, and what kind of Kadee couplers should I install? Thanks.
Click on the “Conversions” tab at the top of the page.
http://www.kadee.com/conv/pdf/b54.pdf
You might want to try the SD 45 one. The 40-2 instructions are for the old truck mounted couplers.
Before you go cutting…what radius are you running? My sense is that radius is the issue.
David B
The smallest radius on the layout is 18" Otherwise I have 22" in other parts.
Something to watch out for when you mount the new coupler and draft gear box - make sure it is centered on the loco center line. Otherwise you could have derailments happen more when running on one hand curve versus the other hand. Been there, had that happen. Also, make sure the draft gear box is level front to back (doesn’t tilt up or down) - that could make you think the coupler is too high or low, and also lead to unwanted uncouplings. Now if you were doing this in N MT would have a complete conversion kit that would fit in the pilot so no drilling would be required.
'SD’s are 6 wheel per truck ‘road’ locomotives and prefer 22" radius and #6 switches.
To run them in 18"r and ‘snap’ switches may require some drastic measures, such as a longer couplerer (#36) (or ‘swival’) mounts (#454) plus a #31 to raise . Since you state it’s “old”, I wonder how much effort or expense your willing to invest?
What you have is a long engine on a sharp curve that was never designed for the Kadee aftermarket. Kadee has come up with some popular conversions, but it’s not 100%. You may have to experiment. I always kept a ‘conversion’ car when converting to Kadee’s.
The longest coupler route may look funny, but is cheapest. ‘GP’-40 engines do better on 18" r.(future).