Early run 33's and SD70's also had issues with sound cutting out over less than ideal track work. Latter runs were better equipped with capacitance to overcome momentary interruptions. I got my early 33's and 70 working much better with a workaround - swapped out one pullmor wheel set with a steel set. Great connectivity with the rails Worked great. L eventually ran out of them.
If no scale sets end up truly available, you might consider turning down some hi-rail wheels. HO folks with code 100 wheel equipped engines, but code 83 or less rail, do that. It sometimes involves a bit of art as well as science. There's more to a flange than diameter - proper cross-sectional profile helps too.
