BNSF spokesman Gus Melonas says the collision happened Saturday afternoon. The man's identity has not been released, but an Auburn police spokesman told The Seattle Times he was 42 and from Las Vegas.
Melonas says the man's girlfriend was taking the photos. She was not hurt.
The death caused the line to be shut down until 6 p.m.
Amtrak spokeswoman Vernae Graham says the Amtrak Cascades train was carrying about 130 passengers from Portland to Seattle. Some passengers went by bus to Seattle while others waited until the train got moving again.
This is the second fatality on BNSF property in Washington this year. There were 20 deaths last year.