The public agencies have said they are no longer negotiating with BNSF Railway.
Prosecutors say they can't prove it wasn't self-defense.
A 67-year-old man is being held on probable cause murder.
It happened just after 1 a.m.
The incident happened at 46th Street Station.
It happened at E. 35th St. and Hiawatha Ave. around 9 p.m.
Reports say police have taken a suspect into custody.