Reply to "90 degree cross missing part"

You will want to have a pin on the center rail. Easy enough to find or cannibalize a yucky track section for one. If you really must, you could take any of the 4 outer rail pins and place it in the missing center rail one as the outer rails are electrically connected by the metal ties, but depending upon your track and surface, this could create enough of a bump to dishevel a train.