Apps for booking train tickets

I think you need the Carte Avantage Senior to book tickets at a senior discount on French trains regardless of the app used. I would love to be proven wrong about that so I will watch this thread.

Yes, you need the aforementioned card. It typically pays for itself with one roundtrip to, say, Bordeaux or Avignon. There are no senior discounts on low-cost Ouigo trains, but those are best avoided unless the times really fit your needs (they are much less comfy).

If you purchase your train tickets in advance, up to 4 months early, you will pay less than someone purchasing a carte senior and using the discount on tickets sold at their peaks or closer to any given travel date.

What Tocard says is mostly true, but recent changes now mean that even the deeply-discounted advance tickets ("Prem's" fares) benefit from 30% off with discount cards.
With such tickets, you'd typically need 2 round-trips instead of one to make the card worth buying, so you have to do the math. It is less likely to work out positively in a short vacation, but the cards are occasionally discounted (29€ instead of 49€), so it's worth checking that too.

Just finished using Trainline to book tix for seniors. Gare de Lyon to Beaune. Beaune to Collioure. Collioure to Bordeaux. Easy to use and understand website. Bon voyage!

janevallerydavis--I just sent you a private message with questions about Berkeley Springs.