I've been trying to figure out how to connect tpc and transformer to a combo Lionel/MTH command environment and also use my BPC's and then the light bulb brightened.
I hooked all wiring up from a toggle switch to route power to the tpc instead of the tiu and at last no back feed of power to any parts that i did not want powered.
the light bulb part was when I realized if I used the t-2 terminal on the bpc and then change the 4 outputs from accessory-1 to accessory-2 it would not be able to back feed to the tiu success at last!
I serviced an old 2046 and tender set on track and applied power oh what joy to see the old smoke unit come alive and the e-unit buzz and that ozone smell old childhood memories once again were alive and well!
now yes I have lionel tmcc/legacy engines also mth ps-2 and proto-1 engines and when operating correctly I like the newer features but I found myself working more to make the gremlins go away than I was having fun just running trains! sorry folks the new engines do not have that good old 1950's smell but do have some really nice operating features and are nicely detailed but are from a new world and that is okay.
now I can enjoy running trains when things in the command world overwhelm me and need to just run and drift away into a world of long ago now isn't that what it's all about!
I know that others here are still running conventional as well and yet others have moved onto the newer command environment and no longer like the conventional engines and this is okay as all that matters is if we each enjoy what we run on our layout.
have a great train day all