Train is the safest and most comfortable transport from Beijing to The Great Wall. It is fast, clean, not crowded and offers nice views. Travelling by car or bus can take longer when you get stuck in traffic jam.
Trains to The Great Wall (Badaling station) depart from Beijing North Railway Station, which is located next to the subway station Xizhimen on Beijing subway line 2, exit A. Ticket offices are located at the right side of the building and in the basement (less crowded). Ask for ticket to Badaling station. One way ticket costs 19 RMB for the second class and 23 RMB for the first class.
Choose one of these air conditioned trains from Beijing North to Badaling:
Y563 Beijing North 07:26 Badaling 08:25
Y567 Beijing North 09:33 Badaling 10:42
Y571 Beijing North 11:08 Badaling 12:15
Y575 Beijing North 13:19 Badaling 14:28
Y579 Beijing North 15:01 Badaling 16:10
And back from Badaling to Beijing North:
Y572 Badaling 11:42 Beijing North 12:59
Y580 Badaling 15:22 Beijing North 16:28
Y588 Badaling 19:40 Beijing North 20:57
Badaling station looks like this so be sure to get off at the right station. Trains in China are on time so get off according to the schedule. When you exit the gate of Badaling station turn left and walk 1000 meters. Entrance to The Great Wall costs 45 RMB. Opening Hours are 06:30-19:00 in summer and 07:00-18:00 in winter.
Badaling Station
If possible, avoid weekend and chinese holidays, because of the crowds on the train and in badaling. Also, the train runs past the site of badaling, stops (so don’t leave!), and then ride backwards a few miles to badaling station.
Furhermore, in badaling you may choose climbing the east side or the west side of the wall. I’ve done them both, west side is much less crowded and offers a spectacular view on the east side with the wall running up and down several hills.
I went back to Beijing taking bus 919, it takes about 1.5 hour to Deshengmen on the second ring of Beijing.