HO scale-sized FRED

This is a removable blinking red FRED with no wiring inside the rolling stock. It has a scale-size FRED with a small black unit hidden under the coupler box and wipers on the nearest truck. It clips on and off, no screws.

I have it working, kind of. it works on a short test track, DC or DCC, but not a layout with a loco on the track - must be inductive or capacitive effects.

Neeed time to get back to it.