A railroad conductor working at the Long Island Rail Road, a commuter train system in New York, found a bag containing two jewelry portfolios storing a total of 36 diamond ring settings worth about $100,000.
Jonathan Yellowday made the discovery on Thursday after a jeweler riding the train left the valuable bag behind.
"It almost didn't seem real. I thought, this can't be what it seems," Yellowday, who has worked as a conductor for eight years, told NBC New York, who first reported the story.
Yellowday turned the bag full of jewelry over to the Metropolitan Transportation Authority Police Department, where the jeweler later retrieved his belongings.
The jeweler realized he lost the valuable bag after arriving home.
"I started searching the house, I thought I brought it home. I started retracing my steps and remembered I left it on the train," the jeweler, who did not want to be identified, told the news station. He was also grateful to everyone who helped returned the diamonds.
Yellowday received a commendation from Long Island Rail Road President Phil Eng on Friday, praising his actions in helping find and return the rings to the jeweler.
In addition to being recognized for his good deed, the jeweler further expressed his gratitude by promising to craft a piece for Yellowday in the future, NBC New York reported.