Unfortunately there is no way of reserving this for passholders outside of visiting a ticket office in Spain.

You should look at the regular fares from RENFE as it is often quite cheap.

Other people have reported being able to pay for a reservtion onboard, preferably speaking to the train staff before travelling.

Then i will try to get it in the train ans ask the Staff, thank you!

Do you think 20 Minuten to change trains in Lyon is enough time? As i travel from Bern to Geneva and afterwards to Lyon. In Lyon i only have 20 Minutes.

Welcome to Spain… no online reservations, that's Renfe for you.

I very much doubt that train will be fully booked. There are still at least 9 seats in 2nd and in 1st class (see renfe.com). The train starts in Lyon, so go there in advance (20 minutes or so) and just speak with the train staff. They'll all know by now that pass reservations outside of Spain are not possible and I've read several successful reports about doing this.

20 minutes is enough if your trains are on time. You can also leave Bern an hour earlier and then you'll have more time in Lyon.

Thanks no i am not so concerned& stressed anymore :)

As there’s only one (direct) train per day I’d recommend you to take the train one hour earlier as French trains are not always as on time as Swiss ones and then you have time for a small lunch in Lyon and enough time to talk to the staff before departure.