Beginner transformer/power and wiring questions
Ok, let me first start off by saying that the layout I am constructing will be 100% protosound 2/3 and dcs. My only previous experience has been with a single loop conventional ac layout. On this new layout I will only be running two trains at the same time with around 5 lighted cars on each. However I plan to have 3 other trains sitting on non-powered sidings that are connected to the rest of the layout. I am also planning on having somewhere between 10-20 lighted buildings, which will be powered by a separate transformer.
Question 1: How many watts will I need to run these two trains and the lighted cars well? I was thinking of the Lionel gw-180, but can this be connected to the dcs tiu? And if so which input would I put it in variable or fixed. As this will be a pure dcs layout I would like to apply a constant fixed voltage to the track, is this possible with the gw-180? Maybe 180 watts is too much or too little power, or simply not a good choice for a dcs setup? If the gw-180 is not ideal, how would you recommend powering this layout?
Question 2: My next question is for powering lighted buildings and such. Basically I just need to know about how large of a transformer I need to power 10-20 lighted buildings? Any recommendation on specific transformers for this? And can I wire a terminal block straight to the transformer and then to the buildings or is there extra equipment needed?
Question 3: Finally how can I wire it so that I can cut power from certain sidings and restore it easily. My understanding is that even idle trains suck up track power, so I plan to have the three trains not in use sit on sidings, and cut the power to those sidings. When I want to change trains I will park one of them onto a siding, turn power off of that siding, turn power on for a siding that has a different train sitting on it, and bring that train onto the main loop. How can I achieve this?
Additionally I will be using mth realtrax if that makes any difference. Thanks for any help or recommendations you can offer.