Do we buy these senior cards at the train stations in Frence? I've read that they cost 55 euros, but can save you up to half on train fares. Will they sell these senior cards to US citizens? Do I wait to make train reservations until after I buy my senior carte? I wish to travel from Paris to Nimes on the TGV the day after I arrive in Paris. Do train reservations sell out or cost more if I wait that long to make reservations?