May 18, 2018 - 5:10 PM
in reply to Gregg57
Hi Gregg57 and welcome to MySwissAlps!
The Jungfraujoch runs daily, year-round so normally there are no planned maintenance days. You can always use the Swiss railways timetable to see what the schedule is on the day of your planned travel. If they had to shut it down it won't show you a connection "Connection not found" for example but not sure that has ever happened.
Maintenance closures are only for cable cars (typically).