# USA SD70 couplers



## Terry Jackson (Jan 4, 2008)

Today I ran my Katy SD-70 for the first time pulling some cars and noticed on my layout that on the curves the first car comes uncoupled and derails on the curves. Apparently the curves on my track may be a little tight, but the diesel itself has no problem running. I used a wire to hook the engine coupler to the box car coupler and watched it go through the curves with no problem. I notised that the swing of the diesel coupler is kind of tight and spring loaded and doesn't have enough free movement to go through my curves. I am sure there is a fix for this problem. I guess i could attach the hook and loop coupler, but would rather have the knuckle coupler. Any suggestions?


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## eheading (Jan 5, 2008)

Terry, what I have done in this case first is remove the spring tension on the coupler. This may be enough to stop derailing your trailing car. If that doesn't do it, you can always open up the hole in the engine, where the coupler passes through, so that the coupler can make a slightly wider swing.

Ed


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## aceinspp (Jan 2, 2008)

I had a similar problem and I did as Ed mentioned is to remove the spring but I also enlarged the coupler opening so the coupler could swing further from side to side. This took care of the derailing car problem. Later RJD


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## Greg Elmassian (Jan 3, 2008)

See my web page:

*http://www.elmassian.com/trains-mai...nu-36/sd70* 


For 2 different methods to increase coupler swing to counteract the extreme overhang of the SD70.



















Regards. Greg


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