Help.  Scenerio.  I have an older ZW transformer which operates three train sets all on modern fastrack.  before i set up i did inquire with the dealer and they noted no problems running new fastrack with an older ZW.  We ran this all last year with no problem.  This past week as we were operating the train sets, two cabooses with interior lights suddenly had their wiring fried.  At the same time we noticed that the lines from the transformer to the terminal track also had wires that were melting.  although i've had no elaborate track plans and have always used a basic set-up, this was the first time i've ever seen this happen to any of my lionel trains, and i've been doing this for many years.  would this be a problem with the track or the transformer or something else.  as a note i checked the engines and all is fine, they still run great.  what would cause the terminal track wiring and the interior caboose wiring to fry.  On one caboose i actually saw the smoke coming from it and shut down immediately.  thx...mike