In December, a 33-year-old music writer dropped his iPod onto the B train tracks at 110th Street. He jumped in and was killed instantly when a train entered the station. The victim’s mother was quoted by The Daily News as saying her son was “very young and kind of adventurous, so maybe he thought he could pull the iPod out of the tracks.”

Image A picture of Mr. Gomez in his family's home in Brooklyn. He tried to help Ms. Briceno, who sought to retrieve a fallen jacket. Credit... Robert Stolarik for The New York Times

Impulse, intoxication, love of risk: It is never clear why people put themselves in harm’s way. Those who have successfully retrieved items from the track say the behavior is more common than people think — but they almost always come to regret it.

“There are a thousand things you can do in this town that are, on paper, unwise,” said Thomas Beller, an author who wrote about his own foray to retrieve an iPod. (It took him two tries and a cut shin to make it out.)

“They could have tragic ends, but people do them all the time anyway,” Mr. Beller said, citing bicycling without a helmet and exploring Central Park in the city’s grimier days. When he told friends of his adventure on the tracks, “it was universally greeted as something that was totally nuts,” he said, adding, “It always get a laugh, but it’s a kind of nervous laugh.”

Mr. Beller, speaking on the telephone, was interrupted by his daughter, newly arrived since the subway incident. “Let me add,” he said, “that once you become a parent, the nature of those calculations changes.”

Transit officials say that in the event of a lost item, passengers should alert a police officer or transit worker, who can often arrange for a hook or net to retrieve the item.

“It’s just not worth taking the risk,” said Paul Fleuranges, a spokesman for New York City Transit. “In one instant the coast looks clear, and you think you can hop down, retrieve your item and hop back up. In reality, it’s not that simple.”