Reply to "Metal vs. Plastic Gearboxes for Kadees"

I prefer metal, but use plastic boxes on brass cars. The plastic box insulates the car from the metal couplers. The mounting screw provides the strength that prevents misalignment of the coupler under load. Over-tightening the box will inhibit coupler movement, though, so be judicious in tightening things down. Kadee 806 and 743's only come with plastic boxes.