During the nineteenth century, the U.S. Congress encouraged railroad companies to build transcontinental railways across the Great Plains by giving them land grants. At that time, the federal government owned most of the land on the Great Plains. The land grants consisted of the land on which the railway was built and alternating sections of 1 square mile each on either side of the railway to a distance of 6 to 40 miles, depending on the location. The railroad companies were free to sell this land to farmers or anyone else who wanted to buy it. The process of selling the land took decades. Some economic historians have argued that the railroad companies charged lower prices to ship freight because they owned so much land along the tracks. Briefly explain the reasoning of these economic historians.