Darwin Award candidate

"Bravo star and fitness instructor Greg Plitt did NOT die from stumbling on a railroad track Saturday ... he was fatally struck by a train after trying to outrun it ... to prove the effectiveness of an energy drink.

Law enforcement sources tell TMZ ... they have reviewed video of the accident and it shows Plitt standing on the tracks as the train barrels toward him. Shortly before the train reaches Plitt he assumes a runners stance and bolts down the track...

And law enforcement tells us they found multiple energy drink bottles near the track and authorities think Plitt may have been hopped up from the caffeine. We're told he was shooting a commercial for the product."