Long Island Rail Road assistant conductor Jonathan Yellowday earned a commendation and 15 minutes of NYC-media-market fame for discovering — and quickly turning in — a ring case containing 36 diamond semi-mounts worth $107,000.

A Manhattan Diamond District jeweler lost the rings while traveling home to Long Island on the Port Washington line. The valuable case was making the trip with him because he wanted to show a variety of popular styles to a niece who is planning to get engaged.

But during the trip, the jeweler got distracted when he met up with a friend. He lost track of time and was surprised when the train arrived at his stop. He rushed through the train doors just before they closed, but left behind a plastic bag containing his ring case.

Working the 6:11 train on Thursday night was Yellowday, who noticed the unattended bag as the train came to it final stop. He collected the bag and brought it to his compartment on the train.

“I had to do a double take because I couldn’t believe what I was seeing,” Yellowday told The New York Daily News. “I actually thought they were fake until I saw the price tags.”

Even though Yellowday was at the end of his shift and the LIRR headquarters in NYC was 55 minutes away, the assistant conductor decided the best thing to do was to hand-deliver the case of diamond rings to the MTA (Metropolitan Transit Authority) police that same night.

“I found a cell phone and a wallet here and there, but nothing like this," the eight-year LIRR veteran explained. “I said I want to personally hand it over to the MTA police to make sure it didn’t get lost in transit. I didn’t think twice about it. That’s somebody’s livelihood in that box.”

The jeweler didn't realize he had left his ring case behind until Friday morning.

"I started searching the house. I thought I brought it home," he told NBC News. "I started retracing my steps and remembered I left it on the train."

He drove to a nearby LIRR station, where the station manager reported that his jewelry case had been turned in the night before.

The jeweler and his wife took the next train to NYC, where they got to retrieve the jewelry and meet the honest man who saved the day.

“I could only imagine what you were going through yesterday when you realized that you didn’t have your jewelry," Yellowday told the jeweler. "You know when you get on the 6:11 you’re in good hands.”

Yellowday and the jeweler exchanged a warm hug. Then, the assistant conductor proudly held up his commendation while posing with some LIRR bigwigs, including LIRR president Phil Eng. Later, he would enjoy a lunch date with the jeweler and his wife.

NBC reported that the jeweler plans to reward Yellowday with a custom piece of fine jewelry.

Credits: Photos by Marc A. Hermann / MTA.