We have a similar conductivity issue with "dead" AtlasO 2 rail turnout frogs. There is a manufacturing/design weakness with AtlasO turnouts - the electrical path between the cast rail/frog pieces and the metal feeders molded into the plastic ties sometimes fail. To prevent the problem I solder feeder wires directly to the cast frog. It isn't easy to solder to the cast metal but with enough heat and flux it can be done. As others have pointed it is important to shine up the metal on the casting. I carefully use a motor tool with a cut off wheel (eye protection a must..) to grind the finish on the side of the casting. Then apply flux and tin the casting with solder. Pre-tin the feeder wire and then solder the wire to the casting. If you use a high heat gun you can get in and out before the plastic ties melt. I use a dual heat Weller 260/220W gun.