what corp is the single largest user of U.S. railroads? measured by $$ spent.?

Question

i read somewhere that United Parcel Service is the largest user of U.S. railroads. thoughts?

Answer 1

This is nothing more than a guess, but I think it is automotive, lumber, aggregates, corn syrup, or coal. Based on the cost of the product being hauled I suspect that autos is the largest user by $$$.