Is it necessary to book trains in the Jungfrau region?

Question

Information

I will be staying in Interlaken with 4 whole days to kill from the 25th of this month.

I would like to do some hiking in the region. For example, getting day-return train tickets to Grindelwald and/ or to Lauterbrunnen.

I would also like to have a trip up to Jungfraujoch.

Questions

Firstly, is it advisable to book (either of) these journeys in advance? If so, how far in advance and by what means?

Extra information

I have read in the "Rough Guide to Europe on a Budget" that to get to Jungfraujoch it is better in their opinion to take cable cars. I am happy to either and so the above questions really apply twice: to trains and to cable cars.

Note: I have an InterRail pass.

Answer 1

There is no need to book anything in advance here. Go to the station, buy a ticket and take the train. After checking at interrail.eu, it seems that the trains from Interlaken to Grindelwald and Lauterbrunnen are not included in the pass.

There is no cable car to the Jungfraujoch. You have to take a train from Grindelwald or Wengen to the Kleine Scheidegg station. From there you proceed by a second train to the so-called top of Europe. Both these trains are rack railways. Maybe the author of the "Rough Guide" was a bit imprecise on that ... Note that the Jungfrau railway is not included either in your Interrail pass.