LOS ANGELES >> In the hustle and bustle of mass transit, riders rush the doors at train stations and bus stops, intent on making that appointment or getting to work on time.

It’s inevitable with a system that gives 34 million rides a month that hurrying customers will leave stuff behind. What is not obvious is that those items are scooped up and brought to the Los Angeles County Metropolitan Transportation Authority’s Lost and Found.

In the lower Arroyo Seco neighborhood of Montecito Heights, steps from Metro Gold Line’s Heritage Square Station, a nondescript, cinder-block building houses tens of thousands of lost belongings that are tagged, logged and cataloged. They exist in drawers as pieces of someone’s life crying out for a reunion with their rightful owners.

Cell phones, wallets, eyeglasses, car keys, laptops, tablets, backpacks and the occasional set of dentures end up in plastic baggies after being sorted by Ruth Moreno, senior agent with Metro’s Lost and Found. Larger items include: bicycles, skateboards, surfboards and one time, a prosthetic leg, according to a Metro report in February 2015.

“The weirdest thing? A backpack with a mannequin head. It kind of threw me,” she said, laughing.

• Photos: Recovery of lost items at Los Angeles Metro rail lost and found

About 200 people every month come knocking on her door and the frequency is increasing, she said.

“Yes, it has been growing. Like maybe 100 more items each month this year,” she said, during an interview at the facility located at 3571 Pasadena Ave.

A huge bump in lost items took place between May and August, she said, possibly a result of the Expo Line extension, which opened at the end of May that leads to Santa Monica from downtown Los Angeles, and the Gold Line Foothill extension to Azusa that opened in March. “Yeah, the summers are very bad here. Everybody leaves their stuff behind. I think it is because everybody is outdoors and you can go further out,” Moreno said.

Often, riders forget to remove their bicycles from the front of the bus. Moreno says ghost bikes ride the trains for an entire day because they are locked to a pole. The number of lost bikes is so large they are housed in a separate warehouse because the stacks at the Pasadena Avenue building are overloaded.

Moreno estimates about 60 percent of the lost items are returned to their owners. The rest is auctioned off to the public once or twice a year at a facility in Carson. Unclaimed wallets, keys and all personal information is destroyed. Nothing is tossed into the trash, she said.

What’s most at stake? Personal data such as family photos, friends’ phone numbers and work contacts contained inside cell phones.

“This is very important to them, stuff they can’t retrieve anywhere else. It is personal to them,” she said.

Moreno uses a one-way window to watch and listen as customers describe their phones or backpacks. If they provide phone contacts she’ll check that out for a match. Sometimes, she’ll ask the person for the number and call it. This bit of detective work helps her make sure phones don’t fall into the wrong hands.

What’s most rewarding, she said, is how people react when their stuff is returned.

“Some of them jump up and down in the lobby. It is amazing how happy they get,” she said.

• Video: Metro lost and found

One older woman brought her a homemade apple pie for finding her purse.

“She brought it to me. That was so cute. She had left $300 in her purse and it was for bills. Her cell phone was inside and I called one of her relatives; that’s how she got her purse back,” Moreno said.

Today, Metro deposits the cash and if someone claims the wallet or purse, a check is sent to their home.

In the old days, conductors handled customer emergencies on their own.

Tom Savio, executive director of the Los Angeles Union Station Historical Society, once found $125 in cash in an Amtrak station phone booth in the city of Davis, Calif. He brought the cash to the local police department.

He recognized the woman when she came back looking for the money the next day and he pointed her to the police department. “She was in tears,” he said. “That may have been all the money she had.”

Possibly the most famous item lost on a train was the manuscript to T.E. Lawrence’s “Seven Pillars of Wisdom” (the basis of the Oscar-winning movie “Lawrence of Arabia”). It was left on a train at the Reading railway station in England and never found. The author had to rewrite most of the book from memory, Savio said.

Alan Weeks, 84, of Eagle Rock, rode the last Pacific Electric Red Car train out of Glendora into Los Angeles. He remembers taking a street car in Toronto and leaving his umbrella on the seat. After waiting and waiting, he went to the end of the line for the train to come back. “The operator handed it to me. That was really neat,” said Weeks.

Moreno said many people don’t think about calling Lost and Found. Often, they lose important papers such as passports and green cards. If they did inquire, her success rate would rise. And she wouldn’t have to melt down unclaimed keys or destroy cell phones, which is exactly what happens after 90 days.

“I wish those numbers were higher,” she said.

To reach Metro Lost and Found, call: 323-937-8920 or go online at: lostandfound.metro.net/public/claims_inquiry.aspx. The building is open to the public Monday through Saturday, 9 a.m.-5 p.m.