Atlas routinely incorporated TMCC for three rail locos for most of the last 20 years.
Same was true of Weaver, but it will vary from loco to loco.
Williams has no command capability.
As noted, you can use DCS to emulate TMCC/Legacy by connecting a Lionel command base to a DCS TIU with the appropriate cable. You can then use the DCS remote to control TMCC/Legacy locos in command mode.
LionChief and LC+ and LC+ 2.0 locos will operate from dedicated remotes (included with LC and LC+) in command mode on a DCS layout. Some of these later Lionel locos also have Bluetooth as a command option using a smart device (phone or tablet), the Lionel universal remote, or the remote that comes with the loco for LC and LC+.
Installing PS3 on a TMCC loco is probably the most expensive approach, and to me, at least, only makes sense if you are MTH DCS only on your layout. One simple approach is have both DCS and Legacy/TMCC available on your layout if you plan mostly on command locos. Your LC, LC+ locos will function well in any of these environments with their own independent command functions.
