<<"Just to make sure, if I book TGV-Lyria from Paris to Basel and hold a swiss travel pass on that day, I can continue to travel in same train from Basel to Interlaken for free right.">>
You pay for the Paris to Basel section by whatever means you like.
Once in Switzerland, if your STP is valid for that day, you do not have to buy another ticket or pay any additional fare. When the conductor checks tickets, you show your Swiss Pass. Occasionally, you will be asked to show your passport to confirm that your identity matchea the STP.
You need an STP for each person in your party. There are special rules/discounts/ tickets for young children and some teenagers. If you have that situation. let us know.
<<"I can continue to travel in same train">>
I'm not so sure about that.
In many cases, when you cross the border at Basel, you can stay on the same train. Sometimes, it is necessary to change trains.
To find out more about that, use the timetable that I linked you to above. It will show whether you have to change trains at Basel.
If, after using the timetable you are still puzzled, let us know.
As you travel in Switzerland, as well as to and from Switzerland, the timetable will be extremely useful. Ut will help you plan any local trips in the Interlaken area, and particularly, the Jungfrau Refion.
As you can see from this panoramic map, there is a lot of mountain transport - rail and cableways, and also buses, covering the area with a substantial network:
www.swissholidayco.com /Public/Assets/User/fi les/Map-of-Jungfrauregion1.jpg
There are many conventional maps of the region as well. Google Maps works, but I lik to use Mapsearch.CH.
If you zoom in to zoom level 32, the railines become very clear.
Also, under the menu item Points of Interest/Traffic, you can turn on layers with the icons for various transport services and the stations. Mouse over the icons, and you will see the exact name of the station, which you can use in the timetable.
The station list timetable is extremely detailed, so that, in addition to the name of a main station, such as Zürich, or Männlichen, there will appear a group of names such as Zürich, Tiefenbrunnen. These are secondary stations or stops within the general area. So, it is useful, but not critical, to know the exact name of the station or stop. If you enter Interlaken in the timetable, you will see a list to choose from includiong Interlaken Ost, Interlaken West, and various local stops such as Interlaken Harderbahn, or Interlaken Ost, See. "See" means "lake" and would be used for lake boat schedules, as well as other services at that station/stop.
We encourage all travelers to become familiar with teh timetab le, and this is your chance to do so before you get to Switzerland.