I once sent an e-mail to Renfe and it took a long time to get the reply. Anyway, most of your questions can be answered by surfing the Renfe site:
* These prices does not include the bed supplement.
Check it here .
21,64 Euros is the price for a seated ticket. If you want to have a couchette, you have to pay 30,66 Euros.
* Children less than 4 years old travel free without taking up seats.
Check it here .
* When you buy the tickets, explain that you want non-smoking seats. The price is the same, though they may not have availability.
* As you can read
here , you can only buy tickets online from 7 - 22 for diurnal trains and for AVE, Lanzadera, Talgo 200 and TRD. That does not include night trains.
You can buy the tickets at the Renfe office at calle Alcalá, 44 (Mon-Fri 8:30 - 20:00) or at the stations.
* Once you find
the schedules from Madrid to Granada on February 1st , click on the
Sierra Nevada train link . You will see the itinerary showing that the departure station is Chamartin.
* Remember that you get
20% discount if you buy a round trip ticket.
* As for the itinerary from Gran Vía to Chamartin, check out the
Madrid subway official site . There is a route planner that will tell you the best way.
Anyway, just take the line #1 from Gran Vía to Tribunal (or also walk to Tribunal), then take the line #10 from Tribunal to Chamartin.
* Dates and times listed on the website are supposed to be correct, but do check them at the Renfe office.
Enjoy your staying in Spain,
Antonio
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The best tips from your favourite hostal in Madrid.
Hostal Chelo at
http://www.chelo.com