I don't have any experience with track bikes or track bike frames but am slightly confused at the replies. Is the frame toast?

If this was a regular steel bike I would strip the paint to fully expose the possible crack. I then would closely inspect the crack itself from the outside and possibly from the inside. If after stripping the paint I could not find the crack I would still try to Magnaflux the area, if this steel alloy is ferrous enough, to see if there is a hidden crack.

Oh... and if it really is a crack, then this frames a crispy critter...