For anyone looking, the Bachmann pigtail board for wiring your own board into the PNP socket , they are now available. This is the socket that is in the newer engines, like the C19, K27, 2-6-6-2, Climax.
https://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=69_772&products_id=12562