The train was traveling from Chicago to Seattle. JOPLIN, Mont. — At least three people were killed Saturday afternoon when an Amtrak train that runs between Seattle and Chicago derailed in north-central Montana, toppling several cars onto their sides, authorities said. At least three people were killed Saturday afternoon when an Amtrak train that runs between Seattle and Chicago derailed in north-central Montana, toppling several cars onto their sides, authorities said. Seven cars on the train, Empire Builder 7/27, derailed at about 4 p.m. local time near Joplin, according to…