Although I model 2 rail, I've converted quite a few pieces of 3 rail rolling stock to 2 rail fine scale.
Here's the Atlas AEM7
The pilot packing piece was made from styrene, as was the blanking piece to fill the original coupling opening.
I made my own kadee coupling height gauge from timber and an old kadee 805.
The trip pins can be bent up slightly with two pairs of fine nose pliers if they're found to be catching any part of the track.
I also make my own packing shims for the 805's from styrene sheet.
Was lucky with this conversion as replacement wheelsets were available direct from Atlas, leaving just the pick-ups to be manufactured.
The engine has a micro-slide switch that changes power pick-up from the overhead wire or the two rail.
When running from the catenary the track power is used for the lights at a constant voltage.
Altogether, a most satisfactory conversion for under $25.