Outside Rails

In my experience with both my home layout and a large club layout using Atlas track is that you don't need to connect a ground to both outside rails.   It will run fine with only one rail connected.  Also, it may be easier to insulate one outside rail to operate signals and other accessories if only one outside rail is connected to ground.

I run trains with TMCC and DCS.   Also, the outside rails are connected at Atlas switches.  

The bottom line is that there is no benefit in connecting both outside rails to ground in my experience.

Joe 

I agree with Dale H 100% .Save one rail for detection.

There's always someone who disagrees.... Best to have feeders to both outside rail especially with engine with traction tires. Some turnouts also loose the  connection  on  Frog side of the switch... If you decide to go with signalling   that's different.

We run DCS with both outside rails connected  beneath the layout