Legacy remote control interference inside metal bridges.

Suggest giving this topic a read:

https://ogrforum.com/...round-plane-wiring-1

If all Legacy locomotives are losing signal inside the bridges, then extending an earth ground (actual house electrical ground) inside the bridges should eliminate TMCC/Legacy signal loss.

Because the track on the bridge is isolated from your layout track, you will need to provide a ground connection between your 990 and the outside rails of the bridge.  You can do this with a jumper from any nearby track or directly from the 990.

@Danr posted:

Because the track on the bridge is isolated from your layout track, you will need to provide a ground connection between your 990 and the outside rails of the bridge.  You can do this with a jumper from any nearby track or directly from the 990.

That would be incorrect, you need to connect the bridge to earth ground and NOT the outside rails!

What's the easiest way to connect to earth ground?

@Windy City posted:

What's the easiest way to connect to earth ground?

The 3rd prong of any outlet is Earth Ground, and you can also pick it up on pin-5 of the serial data connector on the command base.  It's also on the outside barrel of the power connector to the command base, that's where I picked it up for the TMCC Serial Buffer.

Perhaps an additional connection to the bridge will solve the OP's issue.  But isn't there an option in Legacy to have a loco to continue at the last commanded speed and direction until it regains the signal?  If not, it seems like this would be a useful optional setting.

I mean; if it's really a "runaway" you can always kill power to the track.  Or call Denzel Washington and Chris Pine! 

What kind of track?  If you have metal ties on a metal bridge, adding an earth ground to the bridge is a bad idea without isolating the track from the bridge. Any other track that would work.

Marty, that's a good point.  I was thinking to run an small inconspicuous INSULATED wire along the inside top of the bridges, but not electrically connected to them.  This insulated wire connected to earth ground should improve the Legacy signal received by locomotives on the bridges.

@gunrunnerjohn posted:

That would be incorrect, you need to connect the bridge to earth ground and NOT the outside rails!

I am sure you are right, John.  I had a similar problem with my original 313 bascule bridge, locomotives would just drop dead when they got to the span.  Not thinking earth ground, I just solder a wire between the outside rail on the bridge and the outside rail of the approach track.  It worked so I went away happy.  Perhaps that completed the earth ground it needed.

Sometimes things work out, even if you don’t know what you are doing.

@gunrunnerjohn posted:

The 3rd prong of any outlet is Earth Ground, and you can also pick it up on pin-5 of the serial data connector on the command base.  It's also on the outside barrel of the power connector to the command base, that's where I picked it up for the TMCC Serial Buffer.

Like I said it Legacy Steam Locomotives go through the bridges by default if going faster than >20 scale MPH without stopping.  I notice the whistle or other controls do not work during that brief period in the bridges, so signal is lost.  Less than 20 MPH, the engines just stop in the center of the bridges.  Running an earth ground inside these bridges is a bit problematic, due to the fact that they are operational.  The swing bridge and lift bridges operate.  Tough to put a wire through them and have them still operate and run a wire to the bridge, especially the swing bridge.  That defeats the purpose of them being "operational."  I also don't know what you mean by Train Master Command Control "Serial Buffer?"

You can put electrical tape under the metal ties on the metal bridge if you connect an earth ground wire to the track.
Your best bet is to run an earth ground wire next to or best to run it above the track. We did that at our club from a water pipe and above the track in the affected tunnel. Eliminated any signal issue.

If earth ground is connected directly to the track, this will short out the Legacy signal.  The two part Legacy signal is transmitted via the outside rails and is referenced to earth ground.

@trainmanmason the insulated earth ground wire doesn't need to be continuous all the way through the bridge and beyond.  One wire per bridge wire could simply be extended into the bridge area from the bridge pivot side and stop at the other end of the bridge.  Small wire would accomplish this and still allow full range of bridge swing/pivot.  What I'm suggesting is an earth ground bus with multiple feeders extending into the upper portions of each problematic bridge.

The TMCC serial buffer John mentioned, is another application which also required an earth ground source.

I only mentioned the buffer in reference to the place to tap off earth ground, I was faced with the same issue when I designed it.

SteveH, I meant to type not to connect earth ground to the track but only the command base ground there.
I had a similar issue with metal tie track going through a small bridge and put electrical tape under the ties so the track was isolated from the bridge. Any TMCC issues subsided then.
Yes, I know NOT to connect earth ground to the track.
Thanks, Ted

Ted thank you for clarifying.