Do they have a 2 Rail 3 rail switch is it in the 3Rail position, do they have a DCS/DCC switch is it in the DCS position. If you apply power on a test track no TIU what does the amp meter read, still no response?
If not possible a PS blew on the PS-3 board. Weird they all took a hit. Can send boards to evaluate, may be recoverable. G