A veteran BNSF locomotive engineer, a conductor trainee and the shuttle driver giving them a ride were killed when their van was struck by a freight train at a BNSF rail yard near Longview.
Another railroad employee remained in critical condition Thursday at a Portland hospital.
Spokesman Gus Melonas said investigators were looking for a cause of the Wednesday afternoon accident.
The dead are 58-year-old engineer Tom Kenny, a 22-year BNSF veteran based in Seattle; and 28-year-old Christopher Loehr, a conductor trainee since January, also based in Seattle, Melonas said.
Kelso Police Chief Sandy Hamilton identified the van driver who was killed as 60-year-old Steven Sebastian of Castle Rock.
Hamilton said the third railway employee, 52-year-old Dwight Leonard Hauck of Auburn, is in critical condition at Oregon Health & Science University Hospital in Portland.