Controlling switches with DCS and Cab2

You should have what you need to add a command switch to Legacy though I'm not sure how to do it.

For the non-command switches (which I thought you still have) I believe you would need either an "Accessory Switch Controller" (6-14182) or an "SC-2 Switch and Accessory Controller" (6-22980).  The ASC controls 8 accessories OR 4 switches with 10 routes.  The SC-2 controls up to 12 accessories or 6 switches with 9 routes.

I have no clue how to wire this so that both the DCS and the Lionel controllers work.

Since the AIU exactly emulates the manual controls that came with your switch tracks, I see no reason why the switch tracks could not be wired to both the AIU and the TMCC equivalent device at the same time.

Thanks guys.  I figured it would work.  

I wish I would have gone all command switches, it would have made it a lot easier to just have to hook them to the AIU.

I have some Fastrack switches wired to an SC-2 and an AIU, they work seamlessly from either remote.  Both devices have isolated relays that are momentary close for activation, so there's no contention between them.  I guess you could try to switch a switch out on one and through on the other at the same time and have a possible conflict, I don't do that.