I'm not sure what you mean by "N gate" exactly. If by N you mean International gates, those are adjacent to The Club.
If by N you just mean any given Terminal, I'll put it this way going end-to-end on the tram or from the T gates (originally the "Terminal Gates" adjacent to the Domestic Terminal) to the F gates (adjacent to the International Terminal), it's right at 15 minutes of tram time.