Ground wire under track that crosses another track.

The upper track shields the lower track from the airborne signal. So, running a connected to ground wire under the upper track re-supplies that signal.  The ground wire can be connected to pin #5 on the DB9 connector on the base, or connected to the ground pin on the base power supply...same wire.

or the lower signal will radiate upwards and create signal that is out of phase for a train on the upper track. This is Earth Ground, not transformer common. It's easier to do it when wiring than wait until a train stops there later.

The wire size can be small. It's insurance for good running. It's a known condition and good practice to do it.

mknight:

From what I remember - TMCC/Legacy signal is transmitted as a 360 degree circle surrounding the track. When one track is placed above another the bottom of the 'circle' from the top track interacts with the top of the 'circle' from the bottom track effectively increasing the frequency of the signal for the bottom track. A locomotive picks up on this increased frequency - can't figure out what it's supposed to do so shuts down and starts blinking its lights. It is a matter of that loco receiving too much signal not too little.

The New Jersey Hi-Railers club solved the problem using copper foil underneath all scenery for their elevated track. Copper is expensive so I used good ol' aluminum foil under my grass mats. Some have also simply run wire along side the track (not sure if one or both sides). The wire can be coated. It does not need to be bare.

Whatever system you use gets connected to earth ground (this is the third round plug on your wall socket). The ground plane stops the top track signal from propagating below the track surface so it does not interact with the signal from the bottom track. With copper you can solder a wire to the foil. With aluminum you need a mechanical connection (bolt, washers and wire soldered to the bottom washer).

Whether you need it or not depends on what happens with your locomotives running under the elevated track. Try them first before you do any scenery on the elevated portion of the layout.

I used foil but if I had to do it over again I would use the wire.

Joe

Thank You Joe,

That makes sense now that there is an explanation to go with it.

Mike

Moonman posted:

or the lower signal will radiate upwards and create signal that is out of phase for a train on the upper track. This is Earth Ground, not transformer common. It's easier to do it when wiring than wait until a train stops there later.

The wire size can be small. It's insurance for good running. It's a known condition and good practice to do it.

Thank You Carl.

cjack posted:

The upper track shields the lower track from the airborne signal. So, running a connected to ground wire under the upper track re-supplies that signal.  The ground wire can be connected to pin #5 on the DB9 connector on the base, or connected to the ground pin on the base power supply...same wire.

Thank You Chuck