Based on my experience, MTH Realtrax is not be my first choice of a track system. I have a permanent layout in which I use Realtrax for my elevated trolly line. It has electrical connectivity issues. Very frustrating! I've checked and re-checked and then re-checked the track connections and copper connecters , had other folks over who have permanent layouts to get their input, and we call agree that the Realtax has it's own set of issues. I don't mean to sound like I'm bashing MTH, for I like ( and own lots of MTH ) all their other products very much so, but just relaying my own experience with this line of track. I use Gargraves as the track system for the rest of my layout and have no issues. I see in this thread that others use Realtrax and have no issues with it. Again just relaying my own experience with Realtrax. At some point I will replace the Realtrax and use another track system for the elevated trolly line.
If you want to use track with a plastic base I'd recommend Lionel Fastrack. This is what I use for my Christmas tree layout and I've had no problems. Just make sure you put this track ( or any track with a plastic base ) on a base of sound deadening material. Without this kind of base this track produces excessive noise IMHO
There are several track systems out there. I recommend you check all of them out to see what may work best for you. Best of luck!