Your welcome, but all I did was find he link and pass it along. Hope it helps, I realize it's not OE for Tyco/Mantua but in my case I only have a few that I want to keep truly OE. For the rest of my fleet it's chop, cut, drill and make em the way I want. My plan usually works out but not always. LOL One of the biggest problems with the LED's is hiding the wires as they are sometimes larger that the LED. I have used one leg of the LED like a ground on a metal chassis or boiler type engine, then I only have one wire to contend with and that can be covered with the rubber insulation from solid strand wire like Bell wire. Just slide it over the positive wire at the solder joint and push it up to the base of the LED. Works good and it's cheep and ya don't have to heat it like the shrink tubing. Another plus is it stays flexible and comes in colors.
If you guys are interested in building something electronic I was telling Randy about a chuff sound unit that I made and sold many years ago, I could try to find the plans and parts list if your interested in making one? It was all RS parts and I probably still have the PC design, very simple and worked well, it worked off track power not connected to the engine except for setting the chuff rate to correspond with the type of engine your running at the time. Although I have been out of the hobby for so long there may be a product made that I don't know about that does the same thing?