5 ms·

It's not voluntary at all, it's required by the internation convention concerning the carriage of passengers and luggage by rail: https://treaties.un.org/doc/Pu

• lmm 4y ago
  That's only if you have a single through ticket for your whole journey, which is often not possible to buy.
  • logifail 4y ago
    > That's only if you have a single through ticket for your whole journey, which is often not possible to buy. If you don't purchase single through ticket for air travel, you aren't protected if you misconnect either!
    • lmm 4y ago
      Right, but those are a lot more practically available. Most rail routes are only available on a single national operator, and there's rarely any "code sharing".