An Alma, WI, to Black Thunder Mine, WY, coal empty rolls south on the Marshall Sub. The train is working towards the next crew change point at Sioux City, IA. The train crosses the Redwood River couple miles north of Florence along highway 23. Even though empty, this train is about half way up the 30 mile climb from Marshall to a summit south of Ruthton. This is the Marshall Sub, a BNSF secondary mainline that twist and turn from Willmar, MN, to Sioux City, IA, with alot of the mainline tracking in and out along the Minnesota-South Dakota Stateline. Wildfires smoke was doing a great job of creating soupy skies all weekend!