Lionel TMCC / Odyssey loco communication issues

I have engines that behave that way, I think it's a signal reception issue, which is specific to individual locomotives. Earlier models like yours are more prone to this. There are a couple of things that might be causing this. There is a known issue regarding a choke coil on one of the boards. Later versions had a shield added over this coil. I've actually made shields and retrofitted them to try correct or at least rule out this issue.

Antenna length and positioning may also be a factor. I have some very early TMC engines with Pullmore motors that run really well, and don't suffer signal issues that other engines do. Those engines had their antennas mounted vertically in the nose of the engine as opposed to the horizontal plate at the top of the engine in later models.

Another thing that might help is the TMCC signal booster that GunrunnerJohn has been offering for sale. I worked with Dale Manquen shortly before his passing, as a beta tester for the booster. My layout cant run without it.