There is an agreement between most major European train operators called Agreement on Journey Continuation (AJC): https://www.cer.be/cer-eu-projects-initiatives/agreement-on-journey-continuation-ajc
There is an agreement between most major European train operators called Agreement on Journey Continuation (AJC): https://www.cer.be/cer-eu-projects-initiatives/agreement-on-journey-continuation-ajc