Passengers will be able to assert rights stipulated in the R egulation (EC) No 1371/2007 on rail passenger rights and obligations (hereinafter Regulation) as of December - as a rule in the domestic and international transport systems (within EU Member States).
Individual Member States do however have the option not to enforce certain passenger rights stipulated in the Regulation within their domestic rail transport systems straight away. The Regulation namely allows Member States to postpone these rights/obligations entering into force for a period of five years, with the possibility to extend this period. In practice it may thus happen that a passenger purchases a ticket for the domestic rail transport in a certain Member State that has decided to enforce the Regulation gradually, but will be unable to assert the rights stipulated in the Regulation. Below is an example of what may happen.
You have taken a train from Ljubljana to Trieste, where you decide you would also like to visit Venice, so you buy a ticket for the domestic railway transport within Italy. In Venice you find out the last evening train to Trieste, which you have already bought a ticket for, has been cancelled. If you had purchased a return ticket from Ljubljana to Venice, your ticket would be a so-called cross-border (international) ticket and you could demand the carrier to provide you with free accommodation.
However, as you had purchased a ticket for the domestic railway transport (within Italy), you rights will not necessary be the same. Italy may namely decide that certain rail passenger rights stipulated in the Regulation will in Italy not enter into force in December but at a later time. In this specific case you will therefore have to take care of accommodation in Venice yourself on your own expenses; your ticket from Venice to Trieste is namely a domestic transport ticket.