You can choose Interrail or Eurail. With Interrail you can only travel on a maximum of 2 travel days in Romania. With Eurail there are no such restrictions.

Even if you travel with Eurail using your Argentinian passport, you can still use your Romanian residence permit for any border control.

A residence permit is usually not an ID and only valid in combination with an ID, such as a passport.

Hi @Vale 

It is important to point out that in all circumstances, the residency is what counts, even though it is unlikely that the inspector will ask for a residence permit and only the police can actually check the entry stamp on the passport of travellers. This is due to the agreements with the railway and the fact that the Pass is meant for travel outside of your country of origin/residence.

It is crucial to remind that this information is clearly stated on the Conditions of Use of our Passes that can be found here, with a clause 2.3 Country of residence.

Have a nice evening!