Thanks for that link, Ribeirasacra. I will definitely use it the next time I try to navigate the RENFE system.
John,
About getting from the airport to Chamartin, I think metro is going to be quicker and more reliable. The official Madrid metro site has a trip planner, and here's what they recommend:
From the airport on pink line to Nuevos Ministerios. Transfer there to Line 8, and it's 4 stops to Chamartin. They give the total trip time estimate as 40 minutes, and that seems right to me.
From the Madrid bus site,
http://www.emtmadrid.es, it looks like a somewhat complicated trip on public transit from the airport to Chamartin. If I'm reading it right, you have to take the 200 line from the airport and walk a few blocks to change to the 70 line somewhere on the Avenida de America. Total riding time, not including transfers nor waiting, is estimated at 55 minutes. I think you'd be happier on the metro.
One other alternative is a private airport shuttle, running around $30 (dollars, not euro).
http://www.partner.viator.com/en/3465/t ... 0MADAPTHTL I do know some people who have used this, but I think it's kind of expensive and not much cheaper than a taxi would be, especially since Chamartin is on the northern side of Madrid as is the airport.
Laurie