SANTA CLARA — As the express train came hurtling toward the Santa Clara station, Philip Scholz was waiting on the raised platform for his train home when he saw a man down on the Caltrain tracks.

Scholz acted fast. He dropped his backpack, lay down on his belly and reached for the stranger on the tracks.

“As the train approached, the person did want to get out of the way,” said his wife, Emily Scholz, “but between him and Phil, something happened and they were hit.”

Scholz died on the tracks. The man he tried to help survived.

Speaking publicly on Friday for the first time since her husband’s rescue attempt went wrong Monday evening, Emily Scholz said she learned he was dead — and what he did — when San Mateo County sheriff’s deputies arrived at her doorstep that night to deliver the horrible news.

The only person who knows exactly what happened remains in critical condition at the hospital, unable to talk to investigators. Why he was on the tracks is still a mystery — and it also isn’t clear how he escaped death.

But based on surveillance footage, Caltrain knows that Scholz — a popular Silicon Valley marketer — was looking at the man on the tracks, maybe even talking to him before he made his last-ditch effort to pull the stranger to safety.

“It … appears Mr. Scholz was attempting to help the surviving victim, based on preliminary information,” said Christine Dunn, a Caltrain spokeswoman.

The commuter train, however, was barreling through the station at 50 to 70 mph, Caltrain officials said. The express train didn’t stop and plowed into the men about 5:30 p.m. on the Martin Luther King Jr. holiday. Scholz, a 35-year-old Pleasanton resident who worked as a marketing manager for Santa Clara-based computer graphics company Nvidia, was dead at the scene. The identity of the man who survived has not been released.

Scholz’s death left friends and co-workers stunned — shocked to lose a well-loved and respected companion but not surprised to hear he died trying to save someone else. He helped people. That is what he did, they said, even to the extent of risking his life for someone he’d never met.

“That’s totally Phil, putting someone else before himself,” said Matt Conwell of Portland, Ore., who met Scholz 12 years ago in a professional capacity but became fast friends. “That’s the way he was. I can only hope to live life like he did.”

Nvidia co-founder Chris Malachowsky said the act “completely resonates with something consistent with the guy.”

“He was confident, aggressive, capable, I could see that without a moment’s hesitation, he’s going to act,” Malachowsky said. “I’m sure his knee-jerk, no hesitation to help someone else is what caused this — he goes down as a hero in my book.”

A Facebook page dedicated to remembering Scholz soon brimmed with more than 500 “likes,” something Conwell called a “testament to how he lived, and how this guy was loved by friends and family.”

Scholz grew up in Washington state, moving to the Bay Area after high school to attend Santa Clara University. That’s where he met his wife, although they didn’t start dating until after college, eventually moving to Pleasanton together a decade ago.

He made friends quickly at work, at gaming conventions and on the field playing a host of recreational sports. Despite his video-game related job, Scholz preferred off-screen endeavors, Emily Scholz said.

“Once in a while he might sneak away on a Friday night to play ‘Call of Duty,’ but I wouldn’t identify him as a gamer,” she said. “He was a huge A’s fan, and very into sports. And more than just drinking beer and playing softball — he played competitive baseball on a league.”

But he meshed that competitive spirit with compassion and a genuine interest in others that made him very charismatic and “that guy you wanted to hang out with,” Conwell said.

“I’m still in shock and disbelief,” he said. “There’s this residual feeling that this was just too soon, and not very fair.”

Caltrain did not have any more information Friday about the man who survived.

Reeling from her sudden loss, Emily Scholz said she’s not concerned with what investigators find out about why the man was on the tracks.

“It just doesn’t matter at this point,” she said in a tearful phone interview, instead reflecting on Philip’s final act. “I just want people to know that he wasn’t doing something stupid, or that he was in the wrong place at the wrong time. He wasn’t in some kind of argument.

“He was doing the right thing when it happened.”

Contact Eric Kurhi at 408-920-5852. Follow him at Twitter.com/erickurhi.