The zzz train went off the rails Saturday in Manhattan when a straphanger attacked an MTA subway conductor who rousted him from a deep slumber, police and sources told The Post.

Jonathon Davalos, 22 was snoozing on a 6 train at the Brooklyn Bridge-City Hall station in Lower Manhattan at around 9 a.m. when the conductor tried to wake him up for the train’s last stop, officials said.

The irate Davalos woke up and began pummeling the conductor in the face and head, sources said.

He was arrested shortly after the attack and charged with assault.

The conductor, 58, was taken to New York Presbyterian Hospital with bruising to the face.