8889 posts
Have a look at bit.ly/2JQKKSh.
72625 posts
>> on the first weekend of August is there any chance that all seats would already be reserved?
No, there are only specific carriages that can be reserved. There are always carriages that can’t be reserved. For these, you queue (if necessary) and board on a first-come-first-served basis.
>> Do you get a specific time and seat location when you purchase a ticket?
A ticket (as opposed to a reservation) is valid all day, so no specific time and no specific seat. If you make a reservation between Kleine Scheidegg and the Jungfraujoch, you get a specific time, but not a specific seat. The link rockoyster provided goes into detail about this.
>> If you get on in Wengen, will there be good seats remaining if it’s not possible to reserve specific seats?
Reservations from Wengen to Kleine Scheidegg are not possible. If the train is crowded, you will still be able to board, but might have to stand. They do seem to run extra trains when necessary, to minimise overcrowding, and also have separate trains for organised groups.
Alpenrose