A sudden gust of wind blew a baby stroller onto the tracks as a train rumbled into a Brooklyn station yesterday — but a heroic straphanger jumped off the platform and saved the tot from certain death, authorities and witnesses said.

“Right before the train came, I was able to pull up the stroller and myself, too,” said Delroy Simmonds, 30, who was on his way to a job interview when he sprung into action.

“It was just a reaction to seeing the stroller on the tracks.”

Nine-month-old Daniel Zamara took the terrifying tumble at about 12:40 p.m. at the elevated Van Siclen Avenue station on Fulton Street in Cypress Hills.

His mother forgot to put the brakes on the stroller as she was tending to his three siblings, according to witness Khalima Ansari, 21.

A sudden gust set the stroller in motion, and Daniel tumbled onto the J-line rails.

That’s when Simmonds jumped down, scooped up the boy who was still in the stroller as a train headed straight towards them.

“Once the baby was on the tracks, that’s when the commotion started,” the Brownsville resident recalled.

Witnesses were stunned by Simmonds’ selfless act.

“He’s a hero, no doubt about it,” Ansari said.

“Anybody could have thought, ‘Well, I don’t want to lose my life,’ but he didn’t care. He just jumped down and he got the baby just in time.

“The train was seconds away. The driver was honking the horn and then stopped seconds before it got to them,” she said.

The train screeched to a halt a few feet from where Daniel fell.

The baby suffered a head wound and was taken to Brookdale Hospital.

“He’s going to be OK,” Daniel’s dad told The Post. “It was an accident . . . He had cuts and bruises. They put bandages on him.”

Simmonds, who has been out of work for one year after getting laid off from a job helping underprivileged kids, missed his job interview but has another one scheduled for today.

“This is the kind of thing you see on the news but never right in front of you,” he said.

“I just hope [Daniel] and [his] family are all right.”