THE TEHUANTEPEC SHIP RAILROAD vs. PANAMA CANAL. 177 



this weight without injury; by which means all probability of the breakage of one 

 or more wheels affecting the stability of the car, or of strains' from such a cause, 

 is avoided, 



The wheels are separate, each having a disconnected axle, which in con- 

 nection with the straightness of the track above mentioned and the moderate 

 speed at which the car will move, renders derailment practically impossible and 

 therefore removes this difficulty. All irregularities of the track will be corrected 

 by strong steel springs placed above each wheel. 



The body of the car will be composed of plate iron girders, placed laterally, 

 of sufficient strength to sustain the whole weight upon them if they were support- 

 ed only at their extremities, thus insuring an equal pressure upon aU parts. These 

 girders, placed above each set of wheels, will be connected longitudinally by some 

 light though strong frame-work. The great power of the ship to resist a flexure 

 longitudinally, furnishes all the needed rigidity in this direction and makes any 

 extensive connection not only superfluous, but, since such connection would 

 greatly increase the weight of the car, actually injurious. 



Equal transmission of pressure is further accomplished by making the car 

 shorter than the ship, thus compensating the heavier parts amid-ship. 



Upon this car the ship will be supported very much as she would be in a dry 

 dock ; the principal weight rests upon the keel block and the remainder on bilge 

 blocks, but unlike the dry dock, each of these supports is in turn supported up. 

 on a hydraulic jack, all of which, by mean-; of pipes are connected with one hy- 

 draulic pressure. By this simple but ingenious contrivance the ship rests as 

 completely on the water as if she floated calmly on the bosom of the ocean. 



Borne on such a car, straining would seem impossible, while with a maximum 

 grade of only one in a hundred the curvature of which from a level plane can 

 can be made so small that a conformity to it would not bend a ship of the 

 largest size, i. e., some four hundred and fifty feet in length, more than one inch 

 from a straight line, a flexure so slight that it may be entirely disregarded. 



As these are the most practical difficulties suggested we may fairly conclude 

 that there will be no danger of injurious straining to a ship in its passage on the 

 Ship Railway. 



The second objection, viz.: that the weight of its own cargo will produce 

 an undue strain when the ship is Hfted from the water, is even more easily dis- 

 posed of, for in this case we have the logic of facts in our favor ; ships having 

 been frequendy hfted from the water and placed in dry docks while loaded, with- 

 out receiving a strain in the slightest degree injurious. In addition to this no 

 ship is judged seaworthy — fit to meet the shocks and strains of even the lightei 

 storms of the ocean unless it is able to sustain a pressure equivalent to that pro- 

 duced by fining her with water, while in dry docks, to her main deck, a much 

 greater pressure than any cargo could ever produce. May we not then conclude 

 the question oi feasibility as established beyond controversy. 



This point granted, we go further; we contend that besides being as feasible 



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