Re. Power loss on one section when a locomotive crosses it.
Well, I'm no rocket surgeon, maybe this will help.
I use a lot of Fastrack and I experienced your problem (loss of continuity in one section when a loco goes over it) with a heavy Santa Fe FEF, but not with other lighter locos or cars. The problem was a connecting pin that lost contact when the track flexed as the loco passed over it, but was ok when a lighter loco or caboose passed over it. I don't screw my FT down because I have to move it every two or three years (Ok, ok. I'm just lazy). But I also imagine that it is possible to have a short at the wire-to-track connections if there are any exposed wires that can touch each other while the track is flexing. In such a case when you take the weight off the track the short goes away.
Pine Creek and Pufferbelly have good suggestions above. I'm not an electramagician but have figured out how to use a continuity light and multimeter, somewhat. And if you do have a CW80 transformer, you can saw an opening in the side and solder in a cheap automotive in-line fuse holder. It won't look pretty but it works, and any subsequent blown fuses are inexpensive and easy to replace. Some engineer is probably cringing and screaming "There's a reason they made it the way they did, you dummy!" In that case, I suggest you ignore my post.
Plug on. You can do this! And enjoy the season.
PS. If you will be using a lot of Fastrack get a pair of mechanic gloves. My old arthritic fingers work much better handling that plastic roadbed with them on and you won't be as likely to use too much force putting them together, or separating them.
