It is possible to use Eurail to go to Canfranc. But Ouigo does not go to Canfranc and Eurail is not valid on Ouigo.

No sorry it is from Barcelona to Zaragoza, we will take Ouigo but I can see that we can also take renfe

If you see OUIGO web, it is a service for big cities between Madrid and Barcelona like Zaragoza and Tarragona, but Ouigo does not go to Canfranc.

In order to arrive Canfranc, renfe brings a “regional train” from Zaragoza to Canfranc once a day:

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