New ERR install only occasionally will pick up TMCC signal, usually goes right to conventional

FWIW, I've actually replaced a capacitor on several of those with a shorter version.  However, I doubt this is the reason that your TMCC isn't working.

Top suspect is either the antenna isolation or the R4LC has a signal strength issue.  Make SURE the tender shell is totally isolated from the frame and you have a good connection from the antenna connection on the CC to the tender shell.  If you're sure that's 100%, it's probably the R4LC.

Like John I'm betting it's antenna isolation, especially if it's in the tender. If that isn't the cause then swap the R4LC from a functioning unit in and see if the issue is resolved. 

FWIW I had a bad R4LC on a cruise commander I recieved from ERR back in February. So it does happen. I got a replacement from ERR with no fuss. 

@gunrunnerjohn maybe a dumb question.  But have you noticed a pattern of difference in signal strength with die-cast tenders (like the troublesome Greenbrier) compared to brass?  For one thing you can solder the antenna wire to a brass tender shell.  How do you recommend adhering it to a die-cast shell?  I can't help but think that there's a reason why Lionel uses the loco handrails, insulated by plastic stanchions.  It seems that keeping everything in the tender would be much easier.

Tender isolation is a project.  Usually requires plastic screws and an application of very good electrical tape.  Note the plastic grommets (4) in the tender base.  Poor picture but the tender shell, at least where it would touch the base has a liberal application of  33+ electrical tape.  Antenna was attached, shell center where the paint was removed.  All a tight fit.   Very early Digital Dynamics upgrade.  Power board has the metal heat sink.  Second board, with the two TMCC modular boards, is sound.  Speaker rear, facing down under the wiring.   Weaver G5.  

Usually you can find a screw or drill and tap for one in the diecast tenders.  But as stated making sure it is isolated is much more of an issue.  Even an edge of the separate steps or frame touching can kill the antenna by grounding it.  G

Ted S posted:

@gunrunnerjohn maybe a dumb question.  But have you noticed a pattern of difference in signal strength with die-cast tenders (like the troublesome Greenbrier) compared to brass?  For one thing you can solder the antenna wire to a brass tender shell.  How do you recommend adhering it to a die-cast shell?  I can't help but think that there's a reason why Lionel uses the loco handrails, insulated by plastic stanchions.  It seems that keeping everything in the tender would be much easier.

If there isn't a screw in the tender, I find a likely spot and drill and tap a hole for a short screw.  Just find a spot where you won't some through the shell with the drilling!   My insulation is Kapton tape (it's thin and strong), and nylon screws.

The reason Lionel uses the handrails is because the TMCC receiver is in the locomotive and not the tender!  If they put the TMCC receiver in the tender, they couldn't use their IR wireless drawbar, it's a one-way link.