Large Scale Central

Posts on SD70 for coupler have broken off.

General Discussion
#21

Nicolas Teeuwen said:

As a side note, I have removed the springs from all my SD70 couplers, and widened the swing by cutting a notch in the frame so the couplers can swing further. This eliminated issues with the couplers coming undone at certain points on my railroad. The biggest issue i had was with two SD70’s pulling a consist. The front one would often detach and take off leaving the second one to pull everything. I was able to tweak the track geometry in a few places to fix the issues but the connection was unreliable. My conclusion, if pulling SD70’s on 10’ diameter curves, you are best to remove the springs and widen the swing of the coupler for better reliability.

Nicolas,

I am very curious about this as now I wonder if my “prototypical look” mounts will be a problem for some. I assume you are using Kadee “G” scale couplers? Do you know what exactly is happening when the locos detach?

-Dan

#22

Hi Nicolas,

It’s not clear to me what brand coupler or coupler arrangement that is installed in the SD70. For example, does your SD70 have the optional spring loaded low mount USA Trains knuckle coupler - shown below?

Thank you,

-Ted

#23

Ted, The SD70 has the spring you showed in the picture with the springs. I have removed the springs and widened the gap as wide as it could go. This has helped solve issues of them uncoupling with certain cars, and with each other. Its been especially problematic when I couple 2 SD70’s together.

This past weekend I did notice a bit of a side effect of removing the springs. Pushing with the SD70 on long/heavy trains causes the coupler to be mashed to one side or the other instead of being a bit more in the center without the springs. In the past I found that pulling 3 sets of 5 car intermodals worked better when I both pushed and pulled, but that configuration worked less well when I removed the springs.

#24

Dan, I use stock USA Trains couplers on all my rolling stock. Additionally, only my locomotives have body mounted couplers as that is what they come with. The most common detaching I noticed was at transition points for grades. I was able to fix or improve some of those spots but some spots were still unreliable with no clear way to fix it. Removing the springs seemed to work best for fixing the issue.