Post war celebration f3 with tmcc - what do I need

You can run them in conventional mode with the transformer, no additional equipment needed.

To run in command mode, one TMCC command system consisting of the command base and remote is all you need.

Lionel 6-37147 CAB-1L/Base-1L Command Set

John's right on the money.  He's mentioned No. 2 from my list below.

You have two more options as well though.  In order of increasing expense:

1.) CLASSIC TRAINMASTER COMMAND SET (6-12868) -- Original set created back in the day specifically for TMCC. Can no longer be purchased new. You'll have to get them from the usual used sources like train shows, hobby shops, online, etc. This is the Volkswagen solution.

2.) CAB-1L/BASE-1L COMMAND SET (6-37147) -- Can be purchased new from many sources, or used if you'd like to save some money. Runs TMCC well, but will also run a significant subset of LEGACY, an upgrade from TMCC, which provides more features in newer locomotives and rolling stock. This is the Honda solution.

3.) #990 LEGACY COMMAND SET (6-14295) -- Same as above but this runs the full LEGACY feature set. Also can be purchased new from many sources, or used if you'd like to save some money. This is the Cadillac solution.

Be aware that each has two pieces, a handheld unit (cab) and a command base. It may be easier to find, and purchase, the two pieces separately, particularly for #1 above.

In each case there is a one-wire connection from the command base to one of the outside rails on your layout (the antenna). Of the two outside rails pick the one rail that is electrically continuous (unbroken) throughout your layout. Make sure that you plug the command base's power supply (brick) into a properly grounded outlet. This is critical.

(It's a special power brick that has the ground pin for a 3-pin grounded outlet; you don't normally see this on most power bricks.  The ground wire in your house's wiring is the second part of the antenna from the command base so you need the 3-pin connection. )

Mike

With #990 LEGACY COMMAND SET (6-14295), Do I need anything else to bridge the gap back to my TMCC or will it work standalone with my TMCC trains?

@geedubcpa posted:

With #990 LEGACY COMMAND SET (6-14295), Do I need anything else to bridge the gap back to my TMCC or will it work standalone with my TMCC trains?

No. The legacy command set will run any Legacy or Tmcc engine ever made.