The problem is that anything you can do to the toerail, will wear. If you paint it, paint wears (especially if you have cars on it). If you use a deck treatment (StarBrite or whatever) it may look darker and shinier--but will need repeated applications to keep it that way.
You may be able to find a reblacking kit from a gunsmithing supply (Brownell's) that will chemically re-etch it, but that's going to be a slow and expensive process.
I'd put a pin-up on the mast to distract the eyes, and just go sailing.