"How's it work with TMCC/Legacy?"
Metal bridges must be insulated from tubular track ties. I use a layer of grey indoor/outdoor carpet under the track. If track must be secured to the bridge, 3mm black nylon screws (from the river site) work great. Some of the time, the TMCC "ground plane" signal gets through the open trusses. If there's problem with signal reception within the bridge remains, then connect the metal bridge to the ground plane (as discussed on other threads).
