N Scale freight cars jerking, how to fix?

[ednadolski]

I wonder if a small cylinder of foam material inserted inside the spring would work well enough.

I recall trying something like that a (long) while back, but it didn't work out too well.  If you put enough in there to dampen the oscillations, then the couplers stop working and won't stay together (coupled).  Also, I found it hard to cut tiny foam pieces consistently to the small size that it requires.

Ed

[Maletrain]

Cutting small foam cylinders can be done easily with a small hole punch, at least in larger sizes. The whole concept of tiny coil springs in the MTL couplers seems to dampen any desire to mess with them, though.