Exactly how long is a 14 days use? Exactly 336 hours?

I fly in on Monday December 29th to Narita airport around 3pm and plan on taking a train to Niigata.... my final trip would be on leaving Osaka on Monday January 12th at 12 noon going to Narita airport again, but I would arrive after 3pm. Would a 14 day pass cover this? Will it be good as long as I am ON the train before the pass expires? Does the 14 day pass last exactly 336 hours, or in this scenario would it be good until the end of the day (11:59pm) on Monday the 12th?