Madrid airport is connected to the Madrid Atocha station with the C-1 Cercanías line. The Cercanías trains are run by RENFE and can be used with an Interrail or Eurail pass. But unless you're travelling to another city on the same day, it's not worth using a travel day for.

In addition, many Cercanías stations have gates and you'll need the staff to be able to enter or exit the stations.

For ONLY this trip a normal ticket is far better-just an eur or 2.

Note there is ALSO the Madrid metro serving this and the other 1-3 old Terminal-this cost about 5-06 eur from there is of course not included. But if you stay in mAD and want to use transit many times, search for tourist day tickets

You will with IR first have to go to the ticket counter and they can open 1 gate online. IF thats closed=bad luck, no way!

Thanks!!