tons in 1906. At the same time the number of tons of freight hauled one mile for each freight locomotive in the United States increased from 4,000,000 in 1894 to approximately 6,000,000 in 1899, and to 7,300,000 in 1910. In other words, the average performance of each freight locomotive in the United States has increased by more than fifty per cent. in the last decade. The economy of large freight cars has been amply demonstrated. Marked advances in the average capacity have taken place in the last few years. In the sixties a 15,000 pound freight car represented about the normal capacity. This has increased, as measured by maximum load, to 28,000 pounds in 1873; to 40,000 pounds in 1875; to 60,000 pounds in 1885; to 70,000 pounds in 1895; while at the present time 80,000 to 100,000 pound cars are in everyday use. Cars of this latter type, built to carry forty to fifty tons, are necessarily of pressed steel construction, and are mainly useful for the carriage of coal and ore and similar low-grade commodities. It seems to be questionable whether a maximum capacity has not been about reached, in view of the exceedingly great wear and tear imposed upon track, bridges, etc. Up to this point the economy of heavy loading is indisputably proved. Increased size of cars far more than proportionately increases the paying load. Thus, for instance, an 18,000-pound car will carry 20,000 pounds load, while a 22,000-pound car will carry a load twice as great. It is stated on good authority, for example, that a car of forty tons capacity can be built which will weigh but 3,000 pounds more than a thirty-ton car, and cost hardly fifty dollars more. This is undoubtedly the reason why at the present time the average load per car is at least one hundred per cent. greater than the maximum which was possible twenty years ago.