The Lionel Thomas is somewhat limited, conventional operation, no lights, and a very odd sounding whistle. I thought it was time for a somewhat whimsical upgrade. No attempt at "prototypical" lighting was done, as this particular locomotive doesn't appear to have a real prototype, or anything close!
My "new" Thomas sports TMCC control, a much louder whistle and bell, and lights. I used the ERR Mini-Commander 2, the ERR Sound Commander, and a much better speaker. Obviously, a bunch of LED's as well, the rear ones are red/green. The headlights that turn red are from an idea I got in a different forum, I mounted a red LED behind the white ones, works great.
A question arose as to whether the TMCC would fit. Not only did I manage to get the TMCC in there, but the Sound Commander as well. The speaker is in the cab, gives a lot better sound than the tiny one mounted on the bottom did.
Here's the Thomas conversion in pictures.