The railways of the central valley from Santiago south form the most extensive system in the republic. All of these railways, with the exception of a very few branches, belong to the state, and they form a single system which unites the principal sections of population throughout that section. The main track follows the longitudinal valley from north to south in a line which keeps to the same general direction until it ends at Osorno. In its course this system crosses no less than a dozen of the provinces of Chile. Construction has been fairly difficult, and the expense of bridges has been unusually high. There are many long and high bridges, such as those across the Maule, Maipo, Mallico, Laja and Bio-Bio rivers. Most of them have been of French construction. From Santiago to Llanquihue, there are a number of cross railways which run from this main line to the ports, and also some that run inland toward the Andes for a short distance. These were built by the government in its efforts to open up the unpopulated sections. In the carboniferous zone around the Bay of Arauco there are a number of branches which connect the mines, the mining towns and the ports. It will not be long until the railway will be extended to Puerto Montt, which will complete the present plans of the government for southern extension. There are no less than half a dozen transandine railways which have been planned, and for which concessions have been granted by the government of Chile. Two have been completed, two more have had actual work done in the way of construction and the other two are still visionary. One project, which bodes very fair to reach completion, is a railroad that will have for its terminal points the Chilean port of Talcahuano and Bahia Blanca, Argentina. It will run through Monte Aguila and Cholguan, and cross the Andes at Lake Laja. There it will connect with the Great Southern Railway of Argentina, which has already been built from Bahia Blanca to Neuquen, and which is now being extended from there to Chos Malal. The Andes at this point are not nearly so high as farther north, so that fewer difficulties will be encountered in the construction than on those transandine railways which have already been built. It will necessitate a tunnel about one mile in length only to pass the summit. Engineers who have surveyed this route report it as very feasible and strongly recommend it. It is several hundred miles south of both Valparaiso and Buenos Aires, passes through an extremely rich agricultural country and ought to be constructed before many years. It will be of distinct advantage to both republics.