An alleged subway sex attacker has been busted in the assault of a woman at a Broadway and Houston train station earlier this month, cops said.

Police last night arrested 50-year-old Samuel Mangum of Staten Island in the attack on a woman boarding an M train Nov. 10. Mangum allegedly snuck up behind the 42-year-old victim at 10 a.m., assaulted her and then fled the station. She was not injured.

Mangum is charged with one count of third-degree sex abuse.