Atlas track and ground

I think you are talking about earth grounding the secondary side of the transformer? (If not I mis-interpreted your post.) Not necessary with our trains like it is in a commercial or industrial control system to prevent the 'floating' ground.

If you connect the AC hot (usually red) to the center rail and the AC common (usually black) to one outside rail of the Atlas track that is all you need. Try to keep the common outside rail the same one everywhere on the layout. That will leave the other outside rail for isolated rail control of whatever you might want to activate later on. I also use Atlas track and have things wired this way, been working for quite a while with both Legacy and DCS.

I have 500 feet of Atlas track mainline and and another couple hundred feet in yards. I don't have a single instance of connecting the the two outside rails. Every wheel and axle set will make that circuit connection. I once did a test where I ran my entire layouts power thru a piece of track with a boxcar sitting on it. The power ran thru the 4 axle wheel sets of this static freight car and I ran 4 TMCC engines one of which was pulling 8 lighted passenger cars with no problem.

"500 feet"

wow, i can not even relate to that, my little layout is so insignificant in that relationship, i have a total of 80 foot complete,  but that is all i could do, in as much as i had to build a building to house it in, and the structure is 16X12+ a bit due to my yard and septic fields i was limited.  but it is nice, air conditioned heated finished room,  thanks for the input, i guess i was worried about something that was just not a problem,  i put a simpson 260 meter on it and it showed perfect voltage everywhere.

now to figure out all of the requirements for my Ross switches and TMCC interface.

been playing with one of the switches (i like them, very commanding motion when activated!)..  but now to decide what control system.

one question i might ask,   the data line is that a introduced line on a frequency, and is there loss when non insulated wire used,  the switch data lines are plain wire, my experience with data lines in past are all shielded coax.  so i have a lot to learn, considering my last railroad was built when Adolph hitler still alive. i had one engine one transformer and one figure 8 with crossover.   total new to all of this now

You've found the right place for answers to your questions. Guys here are more than willing to help. Thanks for your service. Semper Fi.

I shipped a Lionel item this morning that I sold here on the forum. I was wearing my fairly new Viet Nam veteran cap when I was at the UPS store and they gave me a 5% veterans discount. 

No need for shielded wire\cable unless you find some cheap in the aftermarket.

I use Cat5e plenum rated. It's 24awg, finicky to deal with, but it makes wiring the switches easy. I believe Z-Stuff recommends 22awg, but he 24awg works as you're not pulling at lot of amps for those motors.

The Z-stuff data wire driver on your Cab-1 TMCC base will work great for remotely controlling the switch's and creating routes.

You can switch to Legacy when you think you need it. Call Z-stuff about the data wire driver if you do switch to Legacy.