Reality TV star and fitness model Greg Plitt was killed on Saturday when he was struck by a train.

Authorities said that Plitt was being filmed by two men on a train track north of Burbank, California, when a Metrolink passenger train approached.

According to investigators, Plitt stood on the track even as the train's horn was blaring. They have ruled out suicide and believe that Plitt may have thought the train was on a parallel track.

Plitt was known for appearing on Bravo's reality series "Work Out." His episode on Bravo's new series "Friends to Lovers" is scheduled to air in several weeks. reported:

It was not immediately clear what the men were filming. Investigators are trying to determine who directed them to film on the railroad track.

The men were in a restricted area on the tracks, Sgt. Mark Stohl said.

Plitt also went by the name Greg and was a well-known fitness model.

The actor and West Point graduate has appeared on more than 200 magazine covers, Bravo's reality television show "Work Out" and "Friends to Lovers" and NBC's daytime soap opera "Days of Our Lives," according to a website in Plitt's name.

Watch more above.