TIU / TMCC HOOK-UP

The wire between the command base and the track remains. As you correctly noted, the cable between the TIU and Legacy command base are for communication between those two devices only.

On my layout, I am using all four TIU channels. All the black terminals on my TIU are jumpered and tied-back to the Lionel Command Base.

Thanks Gilly. so just to be clear I am still going to have to connect all of my grounds on the TIU to the Legacy base. is that correct?

I did, so I know it doesn't hurt anything. Some transformers have them tied together internally. If you're using a Z4000 for example, I don't think you need to. I have two Lionel PH bricks and a MRC Dual. So, just to be sure I tied mine together.

Thanks Gilly I appreciate your help.

If you want to operate the Legacy engines in Legacy mode you will need the Lionel LCS SER2. The Lionel wifi unit is not required.

I run my TMCC locomotives (I don't have any Legacy stuff) from my DCS remote. The ground wires from Fixed 1 out, Fixed 2 out, and the TMCC base are tied together, and then the go out to the track. No issues at all that way.