Another important division of the State railways is the line extending from Arica to La Paz. This road, constructed in accordance with stipulations in the treaty celebrated between Chile and Bolivia, October 1904, was built at the expense of the Chilean government at a cost of $11,900,000 U. S. currency. The treaty agreement providing for this road caused a vigorous protest from the Peruvian government, as the route lies through the province of Arica which, previous to the war of 1879, was Peruvian territory, and which is still involved in the Tacna and Arica question. The contract for the construction was awarded on March 4, 1906, and the road was completed in 1912. The engineering difficulties encountered were numerous and complicated, the gradient in some places being exceedingly steep. At one point the line rises 3,610 feet, within a distance of 25 miles. The total length of the line is 267 miles of which 28 miles is of the Abt rack system on a six per cent. maximum grade, which constitutes the longest continuous stretch of rack system railway in the world. The highest altitude reached is 13,986 feet, at a distance of 112 miles from Arica and 155 from La Paz. The road passes through an undeveloped country that is rich in mineral resources, and furnishes direct communication between Chilean ports on the Pacific and the capital of Bolivia. This line, connecting the two republics, and supplemented as it is with numerous branch roads leading into the various mining districts, forms a railway system that has contributed materially to the development of the territory through which it passes. Under treaty agreement it is to be operated by Chile for a period of fifteen years, after which time the section in Bolivia becomes the property of the Bolivian government. LONGITUDINAL RAILWAY. The most important division of the government railway system in Chile, however, because of its relation to the industrial and commercial interests of the country, is the longitudinal line extending from Tacna to Port Montt, a distance of over two thousand miles, and constituting the great central artery of communication, uniting the mineral zones of the north with the agricultural regions of the central valley and the timber sections of the south. This road has as feeders over thirty transverse lines of varying length connecting the productive centers of the Republic with all the principal seaports of the coast. Notwithstanding the fact that transport is maintained by sea along the entire length of the territory constituting the Republic, a north and south railway was felt to be a necessity. In addition to commercial needs there are strategic reasons for a longitudinal line: to facilitate the transportation of troops and armament from one end of the Republic to the other in case of war.