Police confirmed to NBC Los Angeles that Plitt was struck at 4:05 p.m. on the tracks at Front Street, just north of the Burbank Metrolink Station.
Sgt. Scott Meadows from the Burbank Police Department told PEOPLE that the death "appears to be an accident."
"It does not appear to be a suicide," he continued. "A camera was seized as evidence but it's unclear who it belongs to – the victim or a witness. From the sound of it, he was filming something, but I can tell you that no filming permit had been issued."
Plitt was a renowned fitness expert and appeared on Bravo's Work Out and Friends to Lovers, which premiered last Monday.
A Bravo spokesperson told PEOPLE: "This is a terrible tragedy. Our thoughts and deepest sympathy are with Greg's family and friends."
Andy Cohen reacted to the news of Plitt's death on Sunday, writing on Twitter: "We couldn't take our eyes off Greg Plitt after we cast him on Work Out – was as nice as he was beautiful."
"Seemed invincible, like Superman," Cohen added.
Before he became a fitness guru, Plitt worked as a U.S. Army Ranger after graduating from West Point in 2000.
We couldn't take our eyes off Greg Plitt after we cast him on "Work Out"-was as nice as he was beautiful. Seemed invincible, like Superman— Andy Cohen (@Andy) January 18, 2015
Reporting by JOHNNY DODD and EMILY STROHM