Well, I'm here in Pamplona but I thought I share something I never new. Sorry if it's been posted before.
At Atocha train station they have a ticket queuing system which I didn't realise. My train to Pamplona wasn't till 3-05 and I'd arrived at the station just after 12 and was going to have a mooch around but thought I'd buy my ticket first, and I'm so glad I did. I waited nearly 2 hrs in the queue......... so, just warning others that even if you have time to kill, buy your ticket and then mooch around or you could miss your train. It was a Saturday so I don't know if that's why it was so busy but don't get caught out.
Cheers.