In addition to the Atlas Selectors (probably 2-3 Selectors for 8-12 blocks total), you will need 1 Atlas Controller for the reversing section (has 4 slide switches on it).
The reversing section will need to be as long as the longest train to be reversed, and has to have double insulated rail joiners or gaps on all ends.
If the included instructions are not sufficient, Atlas makes a very nice inexpensive book on DC wiring using their components. See your hobby shop or the Atlas web site to get a copy.
my thoughts, your choices
Fred W
I have a 4 X 8 oval with a return loop in the middle. Everything is running fine. I now want to run dual cabs, with "blocks" I will be using Atlas "toggles". I know how to wire the oval for dual cabs, but how do I wire for the loop. The main and the loop are currently being powered by on-off-on toggle switches, one for the main and one for the loop. I hope this makes sense.