I have always had smaller sized layouts and still do. With a smaller layout, "real estate" is at a premium, so accessories with large footprints don't always fit in with the overall scheme of things.
Tfabrizio, you say you have a floor layout and one of your goals with accessories is to not have a lot of wiring all over the place.
A solution I came up with for my layout may also be suitable for your situation.
I have an overhead track that is powered, with a few platforms mounted to it. The track is powered and the platforms are for a few RR types of buildings which are illuminated off the track power. The buildings can be switched, as the lights that are off the track power are positioned to accommodate several building sizes.
On the track, I utilized stationary operating cars like the motorized aquarium car, the motorized chase gondola, the 3520 type of rotating search light car, the motorized walking brakeman car, the flashing toxic waste car, etc. And then, ordinary illuminated cars like seach light cars for added illumination for darkened room running.
To turn these cars "off and on" I utilize small strips of cut drinking straws over the center rail. So when I push the car to the left and inch or so, the car turns off. Back to the right, so the pickup roller clears the drinking straw, it goes back on. For cars with 2 pickup rollers like the modern aquarium cars, I have to use 2 short pieces of drinking straw over the center rail.
So Tfabrizio, you may want to consider placing a straight section of track somewhere in the middle of your floor layout, using the same concept. I don't use FasTrack, but the catalog states every straight and curved section of FT has two terminals on the underside for either track power connection or accessory connection.
But with the shape of the FasTrack rail, I don't know if the insulated drinking straw idea would work as it does on tubular track. Though I should note, some of the newer Lionel cars like the motorized aquarium and walking brakeman cars have an on/off switch on them. Since my overhead track is at the back of the layout, I like the drinking straw idea as it saves me from reaching over and trying to find the small switch on the bottom of these cars. Cars the like the toxic waste car do not have an off/on switch, so the insulated center rail w/ drinking straw idea works great for these.
If you put bumpers on each end of this track (which doesn't necessarily have to be straight - you could have some curves on it), this auxiliary section of track could also double for use with the bump-and-change-direction types of trolley cars.
Just food for thought.
Of course there are the new Plug-N-Play Lionel accessories, designed for layouts like yours. But you are not as likely to find these at the same prices as older gently used operating accessories.