[14] A single locomotive of the New York Central has hauled 4,000 tons of freight at a speed of twenty-five miles an hour. A "camel-back" of the Philadelphia & Reading hauled 4,800 tons of coal from the mines to tide-water without a helper. [15] The Vanderbilt boiler with cylindrical corrugated fire-box invented by Cornelius Vanderbilt, great-grandson of the founder of the New York Central, marks an important step in locomotive building. The cylindrical form largely obviates the necessity of an array of stay-bolts to prevent warping; the corrugated surface gives greater heating power. [16] The Central-Atlantic type of locomotive illustrates a modern improvement. The driving-wheels are placed a little forward of their usual position, while the fire-box, formerly set between the wheels, now overhangs each side of a pair of low trailing-wheels. By this means the heating surface of the fire-box is increased nearly one-half. A lever controlled by the engineer enables the latter to transfer 5,000 pounds weight from the trucks to the driving-wheels when a grade is to be surmounted. The daily run of such a locomotive is greatly increased. (_See cut, p. 61._) [17] A line from Vienna to Triest was opened about 1854; Germany was joined to Italy across Brenner Pass in 1868; France was connected with Italy through a tunnel near Mont Cenis in 1871; in 1882 the traffic of Germany was opened to Mediterranean ports by a tunnel under St. Gotthard. In this manner trunk systems have gradually developed. [18] The building of the West Shore Railroad is an illustration. After both roads had suffered tremendous losses the New York Central settled the matter by purchasing the West Shore. This was one of a great number of similar cases both in the United States and Europe. [19] In Great Britain the ton-rate is about $2.30 per hundred miles; in Germany, $1.75; in Russia, $1.30; in the United States, $0.70. The difference is due as much to the length of distance hauled as to economical management.