I had one, can't say I was enamored. At the time you could order 'generic' rails; I think I got them from Altman's in Chicago. Omega wanted you to send the lens to them so they could grind a custom rail. The generic rails were close enough if you were willing to tweak the focus. The big advantage of the enlarger is that it makes changing the image size painless - you don't have to move the head, refocus, move the head again, refocus again...
Along with the rails you need the right lens cone or the enlarger will never focus. And the enlarging easel has to be 1" thick.