Two straphangers were stabbed early Thursday in separate incidents on subway trains, police said.

One victim was dozing on a southbound 4 train near Nevins Street station at about 4:45 a.m. when another rider sneaked up and tried to turn out his pockets, officials said.

The startled 54-year-old man woke up and began arguing with the would-be thief, who then stabbed him once in the back, authorities said.

The man rode to the next stop at Atlantic Avenue-Barclays Center and got off to flag police. He was taken to Brooklyn Methodist Hospital in stable condition, while his attacker fled the station.

About an hour later, a second straphanger was stabbed in the neck near Times Square during an argument with another passenger, cops said.

The victim and his wife were aboard an A train near the Times Square-42nd Street station at about 6:10 a.m. when the man got into an argument with another rider, authorities said.

When the fight turned physical, the rider pulled out a sharp object and stabbed the other man in the neck.

The victim was taken to Bellevue Hospital and is expected to survive, police said. His attacker fled the train after the assault and has not been caught.

It was not immediately clear what started their fight, cops said.