TANK CARRIAGE.
"Somehow the Spanish Government did not favor the proposal sufficiently to authorize the expenditure of the necessary cash. The matter slumbered until 1814, nearly 300 years, when the Government consented to the undertaking, but the revolution then going on prevented anything like actual work on the road. The Garay Railway concession in 1842 was the next project. Three canal concessions have since been made to Mexicans and one to Americans; then came the concession to Captain Eads for a ship-railway, and last of all is the concession already mentioned for an ordinary railway to be built by an English company.
"We will remark here that if concessions would build railways Mexico would have been gridironed with them long before this. It is probable that two or three hundred concessions have been granted in the last ten years, and nine-tenths of them are not likely to go beyond the 'permission to build' which the concession grants.
"The idea of Captain Eads was that wherever a canal can be built to float a ship a railway may be built to carry one. His theory was laughed at by a great many people, but has been accepted by eminent engineers all over the world who have carefully studied his plans. Like every novel scheme, it has met with much opposition, and many objections have been made to it; but they are chiefly by men whose minds are not scientific. It should be borne in mind that the steam-railway, the steam-boat, the ocean steamship, the telegraph, in fact every great enterprise of modern times, has encountered similar opposition, and in some instances has had no support even from scientific minds. Doctor Bronson says there is fair reason to believe that the ship-railway of Captain Eads will be in operation before the end of the century, and vessels of five or six thousand tons will safely pass over dry land from one ocean to the other.
SECTION OF PART OF CRADLE CARRIAGE.
Scale 1 inch to the foot.
"Captain Eads proposed to build a line of twelve rails, with a grade of not more than fifty feet to the mile at each end. The line descends into the water, to enable ships to be placed in the cradles in which they are to rest during the transit. The grade of one foot in a hundred, or fifty-two and eight-tenths feet to the mile, would carry the line to a depth of thirty feet in a length of 3000 feet. Here the ship, in a landlocked basin, will be floated to a cradle and made fast. The cradle and ship together will be hauled out by means of stationary engines on land, just as ships are hauled upon marine-railways or dry-docks.
"The cradle is an enormous platform car 300 feet long, or it may be a tank of the same length in which a ship can float. In either case it will be the width of twelve rails spaced to standard gauge (4 feet 8½ inches), and will have 100 wheels on each rail, or 1200 wheels in all. This will give a pressure of five tons to each wheel, supposing the cradle to be carrying a ship of 4000 tons, which is no more than the burden of the wheel of an ordinary freight car with its load. Thus is answered the objection which has been made, and very naturally, about the enormous pressure upon the cars and road-bed. Taking the area into consideration, the pressure is no greater than that upon an ordinary railway when a loaded train goes over it.
"The cradle will be drawn along the railway by four locomotives, each of them as powerful as five ordinary freight locomotives of the Pennsylvania or other great railway company. Of course there can be no curves on the railway, as the cradle can be no more flexible than the ship. All bends on the line will be made at turn-tables; but the nature of the country is such that only two of these, or possibly three, will be needed."