TMCC Signal

The TMCC signal is a radio signal.  The system uses the outside rail of your layout simply as a convenient broadcast antenna.  With your layout turned on, the signal exists throughout the room and the antenna in your locomotive on the separate loop is receiving it. 

Note that there are some who believe that the locomotive picks up part of the TMCC signal directly from the rail via contact with the locomotive wheels.  Your observation disproves this notion.

thanks,Bob I always thought the signal came form the track.

If your outside rail of the loop is connected to the outside rail of your TMCC or the common (U terminal) on your transformers are connected together you are connected to TMCC. Don

Actually, the antenna is picking up the radiated signal from the earth ground, the frame connection to the rails is the other half of the signal.  Yes, you can receive enough signal in the same room from the other layout.  However, the contention that the antenna is picking up the signal from the other track is incorrect.

You might visit Dale's TrainFacts page for more information, he's spent a lot of time analyzing the TMCC system.

"However, the contention that the antenna is picking up the signal from the other track is incorrect."

One half of the transmitted signal is from the track, any track, doesn't even have to be connected to any other track.  You only need a few inches (less than a foot) of wire coming off of the antenna terminal on the command base to start propagating a TMCC "track" signal.  The other half of the RF signal is from the house wiring, specifically the ground wires (third prong).  These are the only wires in your house that are all tied together (hot and common aren't) AND they tend to envelope the house and have a strong vertical component.  An SC-2 can be totally isolated both electrically and physically from the rest of the system and still pick up the RF signal and function properly.  

I think that's what I said Chuck.