I am still waiting on the last of the supplies to try this out (12 volt wall wart has been slow from China) but am hoping to do the track wiring piece and what I have this weekend. Worse come to worse I have a 5 amp 12VDC power supply I can use for testing.
One thing I wanted to point out, though from my looking may be a buck or two more but you are starting to be able to get some of the relay modules on Amazon. So for those of you who have amazon prime already, lot faster way to get these components.
One of my other open projects has been learning Arduino to be able to control an outdoor greenhouse. It hit me yesterday while working on some logic that arduino would be a very simple way to control what I was looking for, and not that hard to program(yes Stan, I re-read and saw you recommended this up front 
). I am still going to go the simple electrical method as A everything is here but the wall wart, and B once completed this will run at the layout back in Ohio at my dad's and in the long run I see the simple solution being less stress for him to manager (or me to diagnose with him over the phone should something go wrong). Cost wise also would have been pretty close as the smallest arduino boards can be found for 2-3 bucks and have the inputs needed. The cool thing about using an arduino that I thought of today was you could actually use the system to calculate and or estimate return time, and then display it on a digital or LCD board as "Trolley departs in XX minutes". Multiple ways it could be done, could actually calculate the estimated speed, could put some "check" locations on the path, etc.
For those of you reading this still curious about Ardunio but don't want to dig in too deep, easiest way I explained it to a coworker today was that it is a pc board with inputs and outputs that allow you to control items using simple if/and/or logic. Yes for those who know more about it, it gets much more complicated then this, but it can also just be this simple.
