With SwissTravelSystem tickets such as the "Swiss Travel Pass" or the "Swiss half fare card" you can use the railways in the Jungfrau region at a discount, but not without buying Jungfrau Railways tickets/passes.
On the Jungfrau Railways website you will find further information on the regional tickets/passes required in the Jungfrau region and for the Jungfraujoch and how much discount you receive in combination with passes valid throughout Switzerland (for example in combination with the Swiss travel Pass or Swiss half fare card): |