The marketing of wheat was modernized as well, as the cost of transportation steadily fell and more and more distant markets opened up. Before 1850, the crop was sacked, shipped by wagon or canal boat, and stored in warehouses. With the rapid growth of the nation's railroad network in the 1850s–1870s, farmers took their harvest by wagon for sale to the nearest country elevators. The wheat moved to terminal elevators, where it was sold through grain exchanges to flour millers and exporters. Since the elevators and railroads generally had a local monopoly, farmers soon had targets besides the weather for their complaints. They sometimes accused the elevator men of undergrading, shortweighting, and excessive dockage. Scandinavian immigrants in the Midwest took control over marketing through the organization of cooperatives.