By this time it will be observed that in the discussion of the Chattanooga case we have drifted far beyond the mere competition of rival routes. Commercial competition, which affords the justification for grouping all these twenty-three important southern cities together, is a topic to be treated elsewhere by itself. The difficulty in many of these cases is to distinguish between the really strongest line and the one which is merely the shortest. Upon this point one's decision of the Chattanooga case might actually depend. The Louisville & Nashville contends that Nashville even today is, from an operating point of view, nearer New York than Chattanooga, although the distance is 212 miles more. All the trunk lines compete at Ohio river points, and bring them relatively much closer to New York. The density of traffic on these lines is far heavier than on the air line to Chattanooga. It happens that Chattanooga meets this allegation of greater trunk line density and cheapness by proof of the still greater economy of operation by the coastwise steamers to southern ports, traffic coming thence north by rail through Chattanooga. The appearance of water competition in any of these cases always introduces an almost insuperable difficulty in the way of comparison of long and short lines. Shipment by vessel differs from rail carriage, primarily in the relatively high terminal costs, the absence of all maintenance of way costs, and the low cost of actual propulsion. With a cargo once securely stowed, the distance traversed by a vessel is of relatively little importance, much less so than in the case of carriage by rail. A powerful factor in determining water rates, moreover, especially by sea, is the absence of local traffic. Wharves and terminals being expensive to build and maintain, and the method of loading in a ship's hold not being conducive to ease in access or assortment, vessels are confined largely to bulk traffic at a few important points. The expenses of operation must be more uniformly distributed over the cargo than in the case of a trainload. The water line, therefore, is deprived of one advantage in cutting rates. It cannot, so readily as a railroad, recoup itself for losses on competitive business or at competitive points by falling back upon its earnings from way stations. From all these considerations it not infrequently comes about that, unlike carriage by rail, the longest way round may indeed be the shortest way home. This is clear in the highly involved Wichita, Kansas, cases.[216] Wichita, a commercial centre of southern Kansas, is 200 odd miles southwest of Kansas City. Its all-rail rates from the East are higher than to Kansas City. Yet by the water route from New York to Galveston and thence up by rail, as compared with Kansas City, it is a nearer and intermediate point. The Interstate Commerce Commission well expresses the difficulty: