Art. 48. The Minister of Transportation is to command the studies to be made, to contract for the construction and inspect the traffic of these roads, but he will furnish the Minister of Agriculture a copy of the plans relative to the route and give descriptive memoranda of the project, and when drawing up the papers for the bidding, shall include the clauses which he shall judge necessary and opportune for the colonization of the bordering lands and the development of the industries of the zone tributary to the line as well as to attend to the eventual necessities of the commerce. Art. 49. The construction and the concession for construction of the roads of the second class may be made by the Union or by the States interested. Art. 50. The Minister of Agriculture is the proper person to construct or permit the construction of those Government resolves to carry into effect at the account of the Union, as well as to authorize the payment of the subvention of 15,000 mibreis per kilometer to those which were contracted for by the States. Art. 51. The technical conditions of the railroads of which Art. 45 treats in the second part, are the following: A portable line of the Decauville type. Weight of the rails, 15 kilos per metre. Gauge 0.60 cm between the rails, least radius of curvature 40 M. O. Greatest incline OmO10. Weight of locomotives 18 to 20 tons. Art. 52. The concessions for these roads shall be let at a public bidding according to the rule established in law number 1,126 of 1903, or independently of bidding with a person or corporation sufficiently able with the help of the payment of the maximum subvention of 25 contos per kilometer, according to the difficulties of the land it passes through, paid by sections of not less than 30 kilometers, completely ready and furnished with the necessary rolling stock, within 90 days of the date of the respective inaugurations. Art. 53. The concession for these railroads cannot be given to those who agree to build then simply as transportation enterprises, but only to those who will obligate themselves to colonize and explore, in proportion as they may be justified, the respective marginal lands. It is an essential condition for the validity of the concession, that the contractor presents to the Minister of Agriculture within the maximum term of one year, proof that he has disposed of the lands for colonization, and a descriptive memorandum of the character and extent of the industries he intends to develop. Art. 54. Those railroads of this type which in the future may be joined to any general line of transportation, shall be obliged as soon as its gross earnings amount to 10,000 mibreis per kilometer, to make its gauge conform to the same, and from then for all purposes becoming a part of the general federal transportation system.