Upstream
shot, hanged, sick, broken
Four ways of being destroyed, escalating from violence to disease to total collapse. Notice the rhythm—each word gets one beat, like a drumbeat of casualties.
lucky as plungers
Plungers are gamblers who bet everything on a single chance. The 'luck' is surviving to fight another round, not winning—a dark kind of fortune.
dark sea, great prairie, long mountain
Three American landscapes—ocean (immigration), prairie (westward expansion), mountain (frontier hardship). The mothers are pulling children from geography itself.
Call hallelujah, call amen
Church language—hallelujah (praise), amen (affirmation). He's treating working-class survival as something sacred, worth religious celebration.