Hi David - Welcome to My Swiss Alps.
By the way, when are you traveling?
Swiss Rail tickets and costs, rail passes, regional passes and point to point tickets are complex enough for routine travel, but become more so for the Jungfrau Region. There is no easy single answer.
That is because the various rail passes offer differing discounts on the mountain railways and cableways in the Region.
The standard answer is to look at this link-
and carefully study the details on the maps of validity, varying for different rail/cableway lines.
It is still not easy, and the spreadsheet offered is the most complete solution, but requires a lot of work and planning or guessing.
You would be assisted if you work with a map and the timetable ( this link has very helpful tips and tricks for using the timetable)
After you become familiar with it, you can go directly to the SBB website:
which offers a lot more than just a timetable.
Many maps are available, but this one is particularly good for rail travel:
I have zoomed in to zoom level 32, at which point e rail lines pop into clear view.
Also, in the menu ( star in circle) you can get a lot more specifics about travel routes, schedules, and exact official station names....anywhere in Switzerland.
<<"Do we need a train ticket for travel on gondolas or cable cars. In
other words would we need this train ticket to visit Murren or Wengen to
ski? Would the ski lift ticket provide us with all the transportation
we would need to ski the various areas around Grindelwald?">>
You need a specific ticket for cableways, which is free or discounted, or sometimes full-fare, depending on which one you use. Go to the ticket window, show your rail pass id you have one, and buy or get an entry ticket for the cableway, which gets you onto the cable car.
There is a regional pass or passes that would get you on the lifts and trains around Grindelwald.
Check this page:
A fine distinction - economical intercity public transport is a fundamental right of the population, due to the social policy of the government to help promote countrywide unity, and reduce air pollution from individual travel devices, such as automobiles.
So, since Mürren, and Grindelwald, as well as Lauterbrunnen and Wengen are population centers, tickets between them and Interlaken are highly subsidized. However, if you take a train from Lauterbrunnen to Kleine Scheidegg, the first leg to Wengen is cheap...a few CHF. The same train proceeds on the same rail line to Kleine Scheidegg, which is not a population center. So, that part of the trip is an "excursion" and is priced accordingly higher.
<<" would a second class ticket be adequate considering we will have luggage?">>
Yes. Check the SBB website for details of luggage transport -
but, I think that you will best carry it with you. If you fly SwissAir ( now called "Swiss" ) you may be able to check your luggage in at a station near the Jungfrau, for your flight back home.
The connection through Interlaken Ost has narrow passages, but, there
are frequent trains if you miss the connection. Just follow the herd of
tourists with skiis. ;-)
I don't really understand all the rail passes, so one of the moderators may offer a better understanding, and specific suggestions.
I'm probably wrong but you might find "point to point" tickets ( or Saver Day passes) for the ZHbf-Grindelwald-ZHbf trips, plus a Jungfrau region pass, to be a combination worth checking out. Not clear about optional day trips to nearby places, but the SBB timetable
will give you pries for point to point tickets. Please read the guidelines as noted above...you'll usually see half-fare costs until you dig into the pricing menus. Almost all Swiss carry a half-far discount card......so that is what is listed first