Originally Posted by brumario

Definately the best option is to take the high speed train to Madrid, its much faster as the doors of the train close 2 minutes before departure so if you're in the station 15-20 minutes beforehand you'll have plenty of time. Lots of train frequency as well within the day and the reliability is pretty good.

Beware that this monday June 2nd 2019 there are construction works affecting the Cercanias (short range trains) for some time so it will be a bit more complicated to go with the train to T4 of Barajas. The best option would be to take the direct bus to the airport that departs from Atocha station.

Best regards