Paralyzed with fear, Ksenia Druzhkina watched helplessly as she stood on the platform at Westbrook station, watching the CTrain pull away with her five-year-old son on board.

Moments earlier, Platon had leaped through an open door that closed before Druzhkina, who was struggling with her younger son’s stroller, could join him.

“I was scared,” she said, of Tuesday’s 10-minute ordeal. “But I’m happy this story had a happy ending.”

The boy and his mother, accompanied by younger brother Rodion and father Andrey, returned to the station Thursday to thank transit staff for their part in the happy reunion.

It all began after a visit to Shaganappi library where Druzhkina — who moved to Canada from Russia two years ago — was meeting with fellow immigrants to improve her English skills.

Once at the LRT station, Platon was separated from his mother and got on the train alone. Before she knew it, the doors closed and the train started moving.

Druzhkina frantically pushed the door’s buttons, but it was too late. She immediately used the help phone and was advised to stay put.

Meanwhile, a passenger alerted driver Peter Monrose that an unaccompanied child had gotten on his train. At the next stop, Monrose took Platon to ride in the cabin, showing him light signals and control buttons.

“I was absolutely amazed at how mature he is for a five-year-old,” said Monrose, a driver of about four years. “When I took custody of him, he wasn’t scared. He was relaxed, cool as a cucumber ... It was a bit of a thrill for him.”

For Platon, a self-proclaimed lover of trains, the journey was anything but scary. He said he wasn’t afraid at all, adding: “I was brave.”

At the end of the line, Monrose drove the train back to Westbrook station, watching happily as a tearful and relieved Druzhkina was reunited with her son.

“I hugged him. I asked him, ‘Are you OK?’” she said, adding she told him he was never to do that again.

Andrey echoed his wife’s praises for the responders who helped his family.

“What happened if this occurred in Russia? We probably would have a lost son,” he said. “A five-year-old kid in a one-million city back in 10 minutes? It’s amazing.”

cho@calgaryherald.com