your layout is an inspiration for us all and was the main reason i started to building a train/town myself
(guess i can blame you for my wallet being empty :-P ) when i get my own place with more space i will probably start collecting 12v myself.
as you are something of an expert on the area perhaps you could answer if you really need the sleapers, wouldnt a 2x8 be equally good?
salutations skinkfem