Wiring 2 trains

Yes, you must isolate one loop from the other and have each loop connected to its own transformer. You can run 1 train on both loops with the 2 transformers or 1 train on the complete layout with 1 transformer.

Tstark

Yes but unless I've been instructed wrong you need to wire the transformers inphase or you can fry your engine electronics when it crosses the point it is on both loops power. 

Hey tstark the train store I deal with said the fastrack block sections would not work cause the whole intersection is wired together and can not be isolated.  I cant run two different transformer , it would blow the circuit in the power pack 

FSGSr posted:

... I have them overlapping with cross intersections (whole layout is fasttrack). Is there a way to run each train independently?   

You need to modify your cross tracks from the bottom to isolate each loop.  Turn over the track, and then you can either cut two opposing center rail straps, insulate them from the rest of the track & run an insulated jumper over the remaining strap, or remove the 4 strap "star" completely by removing the screw and loosening all of the folded tabs, and run 2  insulated jumpers crossing each other to get power across the crossing.

That screw in the center holds in the center rail cross on top... you need to choose which track you want to power that cross and run a jumper to the screw also if you remove the bottom straps entirely.  Many trains will be able to cross over without that powered, but some will not.

With regard to the power issue, what transformers are you using?

Im using the standard transformer 80 watts . (I have 2 of them one for each train) I know eventually I will have to upgrade cause every year my display gets bigger

A "standard" transformer can mean a lot of things, or nothing, but if I assume that you mean two CW-80 transformers that are of the same vintage, and hopefully both with a "G" in the date code, then all you need to do is make sure to plug them both into the same outlet / power strip and keep the "A" posts connected to center rails and "U" posts connected to the outside rails, then you are in phase and there won't be any electrical issues.

Keep in mind that this is a different answer than if the transformers were conventional(1033, LW, TW, eg.), or if you were using just one large transformer(Z, ZW, KW, eg.) for the two tracks. Using CW-80s or other similar electronic power supplies in your configuration eliminates a serious concern with unprotected fault currents, so you are good to go.