Locomotive program

Yes, you correctly identified that the R2LC is what stores the TMCC ID and so yes, in theory, replacing that board, if in fact is a bad one, the problem should be fixed. However, there is more going on here. Running away on powerup indicates it is NOT seeing any or weak TMCC signal. That could be an antenna problem or other TMCC problem. The process of then setting an ID then needs to get signal for that to happen, but something as simple as your hand being nearby and other details affect and can increase the TMCC radio signal and reception.

Again, your symptom is more of a not getting signal than a bad R2LC based on experience, but I don't have hands on the engine to really test and only going on what you described.

Hi Bill: Just curious - Make, Model & Product Number?

Bill,                  

Since the problems is only with one locomotive I would believe that it is a board and not a weak signal. If you have another locomotive with an R2LC  that you could try in the runaway, it would be a good starting point.

I will pull the body from the loco tomorrow to get the model and sn and also try the r2lc from another loco,

I removed the shell and found the antenna was laying down along the other wires.  I made adjustments to keep it up toward the top of the body. I then reprogramed the unit number and program.  So far with several system on off cycles everything is running ok. I'm still somewhat skeptical. I will let you know if fix is permanent or temporary.

That would certainly explain it. First, while it's OK, the wire antenna included with the ERR kits is not the end all be all of antennas. The low radio frequency of the TMCC signal is a funny animal and that's why from the factory, Lionel uses strips and plates of metal as antenna or handrails insulated from the shell on steam. Height also matters. I just got one of the new TMCC Ballast tampers, and while signal strength has been great on my layout for most other TMCC items, this one even with it's plate antenna under the plastic shell is lower in height and nearer the track. If I place my hand near the unit that is enough that it suddenly gets reception. So again, height above the rail is a significant factor in TMCC radio signal reception.

https://ogrforum.com/...ntenna-configuration

Another fun topic. https://ogrforum.com/...76#53941752451213876 Possibly too in depth, but just trying to get you some good info on specifics of why I said your antenna being away from the shell and near other wiring would result in an expected reduction of signal- to the point you had the problems you were seeing.

And, the voodoo- that the very capacitance of the human body, you can wave your hand above the engine and affect TMCC signal.