Wanted "leaf spring" type caboose trucks

The only leaf spring trucks I've found are 2 rail.  That includes an MTH 2 rail "caboose" coupler which ironically includes a 3 rail coupler that 2 railers need to cut off.  I bought some when I was in 3 rail and replaced the wheels with some from the MTH trucks I was replacing.  If you are handy, you could probably come up with something for a pickup or use a battery powered setup.   

This is an MTH steel caboose with the replacement wheels.

Precision Scale sells bronze leaf springs that snap in after some trimming.