Go Land Routes

Passengers can travel with dogs on selected AVE Madrid-Barcelona trains and certain AVE routes such as Madrid-Málaga, Madrid-Granada, Madrid-Alicante, and Madrid-Valencia. One "large" dog per passenger is allowed, with a maximum of two "large" dogs per train. Tickets can be purchased 24 hours in advance on the Renfe website.

Renfe (National Network of Spanish Railways) is the state railway company of Spain

More on this: Railwaypro publication

[:en]Renfe local train station in Madrid.[:]
Renfe commuter train in Madrid

Traveling with a pet is now possible in Spain

The Railwaypro online publication reports that Renfe is increasing the number of pet-friendly trains. Passengers can travel with dogs weighing up to 40 kilograms on the Madrid-Barcelona AVE trains.