The Marshall Sub pass right thru the heart of Camden State Park. The park was established in 1935 and was build around the Redwood River which determined the placement of various functional areas in the park. Southbounds trains thru here climb about 30 miles from Marshall to South of Ruthton. Here an Alma, WI, to Black Thunder Mine, WY, empty coal train slowly rolls along the Redwood River as they make their way towards the next crew change at Sioux City, IA.