Well over a half million people pass through New York City's Grand Central Station every day, making it one of the busiest train stations in the world. Since a relatively high percentage of those people forget something on the trains they ride, that makes the Lost and Found department at Grand Central pretty busy too.

In a quiet corridor underneath Grand Central Station, Rich Heggman of the Metro North Lost and Found office opens a small leather case a railroad policeman has just delivered to him.

That camera is just one of between 17,000 and 20,000 lost items that come through the door of this office every year. Wallets, books, diamond rings, cell phones, knapsacks with and without contraband - whatever people can carry on to a train, they can lose there. Office manager Mike Nolan and his boss Fred Chidester examine a 60 kilogram tub of lost keys.

NOLAN: "We have thousands of sets of keys," he said. "That's something we usually don't throw out.

CHIDESTER: "We do collect keys. I'd like to know how some of these people get replacements because a lot of the cars have microchips, they are like $200, $300 keys to replace and you would think that they would come back and ask for them," he said. Mr. Nolan motions toward the back of the facility, which is lined with shelves of crates, each carefully labeled according to content, date recovered, and other relevant facts. "I'll show you our coat racks," said Mike Noland. "We probably have now have 500, or 600 coats. Most of them are blue blazers. There are Armani, Brooks Brothers, any old brand. There is anything from the cheapest coat to the most expensive here."

Some lost items can seem quite creepy to the uninitiated. Fred Chidester recalls dealing with one set of objects contained in dry ice that a plastic surgeon on his way to an area hospital had left behind on an overhead luggage rack. "Yes. It was actually two earlobes and two eyebrows, and he had them packaged up for this reconstructive surgery and left the box and all on the train," he said.

When asked why he thinks people forget their possessions on a train, Rick Hegmann says it may simply be because they are tired. "They're overworked," said Hegman. "That's the problem. When they tend to lose a lot of things, then you know they are overworked. That may be the cause. If they are sleeping and they are dozing off, next thing they know their stop is coming up and they are jumping off the train, and whatever is left behind hopefully comes back to our facility. It usually takes a day or two, but it's usually here."

A full 60 percent of the objects that are lost on the Metro North railroad ultimately get connected with an owner's name. That success rate reflects some real detective work checking such things as credit card slips and serial numbers searching for clues as to an item's owner.

But Mr. Chidester, himself a former police lieutenant, admits that, in some cases, determining a true owner can be quite straightforward. This was the case recently, when two sets of dentures appeared on his desk. "Teeth is [are] a funny thing," he said. "mtch a set of teeth? I don't know how you lose teeth on a train but ? this fellow came in, and we pick it up with a pair of latex gloves and bring it over to him. He picks this thing out of this wrapping paper and looks at it. He says 'well they look like mine. I think they're mine.' He takes this thing and just plops it into his mouth and I'm going 'Aw! Where's the mouthwash?'"

Occasionally, people leave objects on the train on purpose. Fred Chidester offers this grisly example. "The story goes that the husband used to go home on the train and used to give his wife the excuse that he missed the stop or he fell asleep or he was in the bar car and didn't realize that the train had passed his station," said Fred Chidester. "So when he passed away, she had him cremated and put in the urn and she left the urn on the train and said 'Well there! Now you can ride on the train with your buddies and your girlfriends all you want and enjoy yourself until you find a rest.'"