Ground Plane issue--1 direction only?

I once had an issue where the r2lc board had an abrasion on the board trace that disconnected the antenna input to the circuit,  from the board connector that went to the wire antenna. As a consequence the engine would run fine with the boiler off since the r2LC board could pick up the signal. Attaching the antenna did little or no help since the trace on the board was cut. Fixing the trace fixed the problem. Just a thought.

Wouldn't the metal boiler block/ interfere with the signal? Thats why Lionel steamers use the hand rails as the antenna and why its important that the handrails are insulated from the boiler.

Just a guess, but generally speaking metal between the loco antenna and the signal radiated from the ground wiring of the room causes issues.

Thats why chicken wire framed tunnels and metal bridges can cause problems as well.

Turned it 180 degrees around and ran backwards in the same direction or backed it up in reverse where it had just traveled?

Running it in reverse.  Either way.

Just a thought.  Try putting the old DCDR back in, it's a simple replacement.  I seriously doubt this has anything to do with it, but it's the only thing you changed.

I suspect something happened when you did the upgrade, something obviously is different.  I've installed probably 20 of the CCM boards, I've never had an issue like this.

I think I'll try a new board first.  That DCDR is tucked away pretty good amongst some wires, etc.  The nuts for the heat sink are not easy to get at when reinstalling.  

Well, the R2LC is an easy test, so that's certainly top of the list.

Even though I previously tested the handrails for continuity with the shell, I never tested them when everything was put back together.  I tested the handrails against track outer and it came up that they were connected.  So I took it all apart, fiddled with some of the wires, and screwed it back down not so tight.  No continuity now between track and handrail.  Seems to be better.  Hopefully that is the answer.  Now for some long term testing!

That is one of the prime problems with TMCC signals for steamers, so I suspect you're on the right track.

Pun intended?

Easy target.

Would agree an antenna issue.