k-line Hudson

The MB you are talking about is in the tender and is the sound board.  To upgrade to full Railsounds, you'll replace the Signal Sounds board with the two RailSound boards, the Power and the Audio.

The TMCC receiver is in the locomotive, so you need to verify what configuration exists in there and what motherboard is used.  You'll also want to check to see if the handrail antenna is isolated and has a connection to the locomotive motherboard.

I have not looked inside a conventional scale Hudson but the conventional semi scale ones use an electronic E unit. For TMCC you would have to do a complete upgrade. Given these have a single RS385 Mabuchi you should be able to use one of new Cruise Lite boards by ERR.

Pete

There is very little in the engine so this is conventional.

It is worth a look in the engine.  The Lionel Conventional but upgradeable engines used a component 103E board.  You swapped this out for a R2LC and you had a TMCC engine.

I do believe K-line used 8 and 6 pin tethers though.  The TMCC had the 8 pin and the conventional had 6, so there might be some issues integrating the whole package.

At least some of the K-Line TMCC versions used a 6 pin tether, I've got a couple of them.  There may have been an 8-pin version as well, I can't say.