NEW YORK (AP) -- A personal trainer jumps down onto the subway tracks to save an unconscious man as a train barrels down. A trucker stops to pull a driver from a burning car. A quick-thinking plumber uses his belt as a tourniquet to save a woman badly injured in a crash.
In New York City, which often has a keep-to-yourself, don't-get-involved reputation, at least a dozen good Samaritans this past year were willing to risk their own safety to save a stranger.
"It's the way I was brought up: Always look out for each other," said Dennis Codrington, the personal trainer who, along with two others, helped pull up a bleeding, unconscious man who had fallen onto the tracks of the No. 1 train late one February night.
Codrington was headed home from a party when he saw the 6-foot-tall man at the edge of the platform and then disappear. About 55 people are struck by New York subway trains and die every year, and the 24-year-old Codrington wasn't going to let this guy be one of them.
So he and the two others jumped down to hoist the bleeding, heavy stranger up -- as the time clock flashed that another train was due in the station in one minute.
"It was really nerve-racking," Codrington said. "But we couldn't leave him there."
Miami emergency room doctor Ben Abo found himself in a similar dilemma at a New Jersey commuter train stop in Greenwich Village during his summer vacation to New York City. The 32-year-old was headed back to Jersey City, where he was staying, when a straphanger took an extra step and fell off the platform.
"He went down right over the edge. He was walking as if the platform was still there and wanted to take another step," Abo said.
The man fell head-first and lay on the tracks, bleeding heavily. Abo looked to see if a train was coming and jumped in, yelling for the two dozen people on the platform to pull a fire alarm and get help.
Sweating, he heaved the man up overhead, back onto the platform, as someone helped from above, and he then tried to pull himself back up, too.
He felt a gush of wind and saw headlights reflecting off the wall.
"I said to myself: 'You have one chance to get up,'" he said.
He made it and set to work trying to stop the bleeding, while a crowd gathered around him -- holding up smartphones to take video.
Psychologists say some people have the right mix of qualities it takes for risky heroic acts -- altruism, courage, knowing the right thing and being reflexive about it, as well as the ability to inhibit fear that stops most people from getting involved.
"It's not one hero gene. It's a very complex set of characteristics that converge and that person is unique, and thank God for them," said psychologist Dr. Rachel Yehuda at Mount Sinai Medical Center.
Ervin Straub, a professor emeritus of psychology at the University of Massachusetts, who has studied altruism extensively, said crowds in a big city can work against such heroism by creating a "diffusion of responsibility."
"When there are a bunch of people around, there is often a 'Why me? Somebody else can do it,'" he said. "But if someone else developed a strong sense of responsibility, they are not likely to wait. By seeing the others' passivity, their feeling of responsibility may kick in."
A gaggle of videotaping onlookers surrounded 44-year-old plumber David Justino this summer as he tried to stop a tourist from bleeding to death after an out-of-control taxi struck her, severing one leg and badly injuring the other. He used his belt as a tourniquet and poured bottled water over her severed limbs, which were gushing blood.
"I had no choice," he said. "I had to help her, someone had to."
Truck driver Alex Mitchell, 37, of Queens, was alone on the Long Island Expressway two months ago at about 1 a.m. when he saw a man in an SUV driving erratically, then crash into a tree. Mitchell pulled over and ran to the scene.
"There was a flickering of lights, and by the time I got there, it was a big ball of fire and smoke," he said. He reached the man, yanked him up and helped him away from the burning vehicle.
"The only thing I was thinking was, 'We have to get out of here before this thing goes up,'" he said.
Both Mitchell and Justino have since contacted the people they saved to see how they're doing; the tourist, Sian Green of England, is healing.
"There's good people in this world, very good people in this world that I can't thank enough," Green said on NBC's "Today" show in September. "They saved my life. If it wasn't for them, I wouldn't be sitting here right now telling this story."
The driver saved by Mitchell was released from the hospital and later charged with driving while intoxicated. Mitchell said the man, who has four kids, found out his name and left a note at his office thanking him.
Abo got a thank you and a pat on the back from police. Then, covered in the injured man's blood, he boarded another train and went home to Miami.
He doesn't know what happened to the man he saved. Neither does Codrington.
"The last time I saw him, he was bleeding profusely and not conscious," Codrington said. "I wish I knew whether he was alive."