Track Spacing

I have misplaced my trusty NMRA guage. Can someone please tell me what the standard distance between mainline tracks is for HO Scale. Is 2.5" inches between the centerlines of the parallel tracks enough of a seperation?

Thank You,

Ray B.

Follow this link. It has your answers.
http://www.nmra.org/standards/s-8.html

Thank you for the link. It also answered my next question about how much space to allow between parallel track on curves.

Ray B.