TMCC signal won't work.

Up front I am not an expert on TMCC.

I will assume all your other engines are running correctly via TMCC control. The following is based on this assumption.

While you have the tender shell off, please, if you haven't done so already, make sure any and all card to card connections, and cable to card connections, are well made, nothing is loose.

Was the antenna soldered to the metal shell, or to a handrail that protruded through the shell? The antenna must be isolated from the track or the engine/tender won't be able to receive TMCC. If the antenna was actually soldered to the metal shell itself, then the metal shell has to be isolated from frame/wheels. If the antenna is soldered to a handrail the protrudes through the shell, you have to make sure the handrail is isolated from the metal shell.

You mentioned you just had the wire sticking out of the tender. I would get a piece of wire (gauge of wire not important) at least double the length of the antenna wire in the tender which I would temporarily solder to the end of the tender's antenna wire. Hold this wire in your hand off the track, or loop it from over tender and engine. Try the TMCC control again. If this works, I would say the engine/tender's electronics are working for TMCC, and you have an antenna problem to solve. If operation with this longer antenna does not improve TMCC operation, the I suspect your electronics.

Just for reference and edification, I have attached an article from a past issue of O Gauge Magazine about TMCC transmission.

Thank you!!! Yes, all my other engines run fine. The antenna was soldered to the tender shell. I tested the tender shell to the wheels, and it seems to be isolated. I will try what you said with the antenna wire. I am pretty sure I have a antenna problem.

Thanks for your response!!!

I’m guessing other engines run correctly on the layout. Has this engine run fine in the past ?

I’m not that familiar with 3rd rail steamers. I learned a bit watching one of Norm’s videos that shows the factory EOB install. Looks like the chassis along with the shell are isolated from the rails by using some sort of insulator at the axle and sideframe. The outside rail is picked up by wheel wipers to run the electronics.

https://youtu.be/ISIwJT9ZG30?si=izqHoIuADMj32tM6

Besides the antenna, you could have an R2LC with a marginal TMCC receiver.  This can be diagnosed by simply swapping the R2LC board from the ailing locomotive with a working locomotive and seeing if a different R2LC.

Typically, an insulated tender shell is a very good antenna, so if it's truly insulated from the outside rails, I'd be looking at other causes.

John is right on. I had the same issue, replaced the R2LC and all is well.