SUBWAY SADIST

Susp held in sick bash of rider after he was hit by train

A MAN WHO police say knocked a straphanger unconscious and watched an oncoming train hit his victim’s head — then punched him once again — has surrendered to cops.

Benjamin Gonzalez, 24, and another man are suspected of punching Francis Christie in the head on a Union Square subway platform about 2:50 a.m. on Dec. 16, according to prosecutors.

Christie, 41, was knocked to the ground, with his head hanging over the ledge, in the attack, according to a criminal complaint.

An oncoming Q train slammed into his head immediately after Christie fell, shattering his skull.

Gonzalez then pulled Christie back from the ledge and hit him in the head again, prosecutors charge. Gonzalez, of Queens, and the other suspect, who has not been identified, were caught on video surveillance inside the subway station following the attack, officials said.

Gonzalez turned himself Wednesday, authorities said.

He was charged with assault and reckless endangerment at his arraignment. Court records show Gonzalez was released after posting $75,000 bail.

His lawyer Arthur Gershfeld could not immediately be reached for comment or for information on the second alleged attacker.

Christie (photo inset), an artist who lives in Flatbush, Brooklyn, remains at Bellevue Hospital.

His mother, Joy Wells, hailed the arrest.

“I was elated,” she said Sunday. “I figured in New York there are 8 million people, they’ll never find in him. I didn’t think there would be an arrest for a very long time.”

Initially, she couldn’t believe the news.

“(The detectives) just told me they made an arrest, and after that my mind kinda went blank,” the La Junta, Colo., woman said.

On Friday, her son was moved from intensive care into a rehab unit as his condition slowly improved, she said.

“He’s up walking some,” the 65-year-old Wells said. “They’ve had him going up some steps. But he’s still not talking.” She remains hopeful that he will make a full recovery. “He didn’t have his phone for three weeks,” she said.

“He wanted his phone and they took it to him, and he remembered the password.” She talked with her son a few days before the attack.

He was excited about an upcoming art show in Greenpoint, Brooklyn, where he would be displaying several new pieces, some of them created with a new chrome pen, the mom said.

“I was excited for him,” Wells recalled. “I couldn’t wait till he called me after the show to see how people reacted to his work.”