Considering the Catalonia Gaudi in Madrid?
A VT member wrote the following comment about visiting Madrid:
Madrid to Sevilla AVE train by islaazul
The AVE train promises to get you to Seville from Madrid in 2 hrs 10 min or your money back. I didn't truly appreciate this until I got on the RENFE from Seville to Granada (4 hrs), and then the TALGA from Granada back to Madrid (6 hrs). Each was more run-down than the last. I hope they have plans to modernize the entire system...
Go to the station the day before your planned departure so you have a wider selection of departure times.