Powering switches and trackside accessories in a DCS star wiring scheme

"As long as I phase the transformers to those running through the TIU, can I simply do something similar with this layout?"

Yes

"I figure I'd run a pair of wires from one transformer and a single hot from another transformer around the U-shaped layout, then daisy chain connect their two commons."

The Commons from both transformers go to the same terminal strip.  With Star wiring your track commons leave that terminal strip and and run paired with the track variable voltage for best signal. 

The rest of your variable voltage wires can use a common bus from that Common start.  Those wires don't need to be run as pairs of variable voltage and common.  Some accessories may interfere with the DCS signal if the track uses the auxiliary bus

@Susan Deats posted:

"As long as I phase the transformers to those running through the TIU, can I simply do something similar with this layout?"

Yes

"I figure I'd run a pair of wires from one transformer and a single hot from another transformer around the U-shaped layout, then daisy chain connect their two commons."

The Commons from both transformers go to the same terminal strip.  With Star wiring your track commons leave that terminal strip and and run paired with the track variable voltage for best signal.

The rest of your variable voltage wires can use a common bus from that Common start.  Those wires don't need to be run as pairs of variable voltage and common.  Some accessories may interfere with the DCS signal if the track uses the auxiliary bus Not sure I understand your answer.

For mainlines - I'm not so worried about using a shared common. Not sure if that's even feasible, but I plan to run pairs from the transformer to terminal strip and several pairs to the lock-ons on the tracks.

Are you suggesting that the semaphores, gateman, and switches should share a common with the mainlines' transformers (via the terminal strips)? Or, can I wire them totally separately?

I have a separate transformer powering my switches, another for uncouplers, and another for operating accessories. All the transformers are phased to the track transformer. This prevents any wiring mistakes to ground causing issues. All my ground wires are black, so it would be tricky if they were not all phased together. After a while, all those black wires start looking the same.

@raising4daughters posted:

Are you suggesting that the semaphores, gateman, and switches should share a common with the mainlines' transformers (via the terminal strips)? Or, can I wire them totally separately?

You may keep them totally separate.  The "best practice" would be to tie all transformer Commons to a common terminal strip then tap your separate block commons off that strip.