Vitto,
Start checking all the wires in and around your transformers, Breakers & TIU, especially your 24 port transfer blocks, if you use them. Then follow each line track side to assure proper connection and that nothing has been crushed or damaged somehow. You either have a bad track or your wiring has been damaged in some way, causing a major short to occur, or you have something laying across your tracks that you do not see.
PCRR/Dave