CHEAPNESS OF CONSTRUCTION. 



arranged that the time of crossing them corresponds with a meal 

 of the passengers. A platform is constructed level with the line of 

 railway, and carried to the water's edge. Upon this platform 

 rails are laid, by which the waggons which bear the passengers' 

 luggage and other matters of light and rapid transport are rolled 

 directly upon the upper deck of the ferry-boat, the passengers 

 meanwhile going under a covered way to the lower deck. The 

 whole operation is accomplished in five minutes. While the boat is 

 crossing the spacious river, the passengers are supplied with their 

 breakfast, dinner, or supper, as the case maybe. On arriving at the 

 opposite bank the upper deck comes in contact with a like platform, 

 bearing a railway, upon which the luggage waggons are rolled ; the 

 passengers ascend, as they descended, under a covered way, and, 

 resuming their places in the railway carriages, the train proceeds. 

 21. The prudent Americans have availed themselves of other 

 sources of economy, by adopting a mode of construction adapted 

 to the expected traffic. Formed to carry a limited commerce, the 

 railways are frequently single lines, sidings being provided at 

 convenient situations. Collision is impossible, for the first train 

 which arrives at a siding must enter it, and remain there until the 

 following train arrives. This arrangement would be attended 

 with inconvenience with a crowded traffic like that of many lines 

 on the English railways, but even on the principal American lines 

 the trains seldom pass in each direction more than twice a day, 

 and their time and place of meeting is perfectly regulated. In the 

 structure of the roads, also, principles have been adopted which 

 have been attended with great economy compared with the English 

 lines. The engineers, for example, do not impose on themselves 

 the difficult and expensive condition of excluding all curves but 

 those of large radius, and all gradients exceeding a certain small 

 limit of steepness. Curves of 500 feet radius, and even less, are 

 frequent, and acclivities rising at the rate of 1 foot in 100 are con- 

 sidered a moderate ascent, while there are not less than fifty lines 

 laid down with gradients varying from 1 in 100 to 1 in 75 ; never- 

 theless, these lines are worked with facility by locomotives, without 

 the expedient of assistant or stationary engines. The consequences 

 of this have been to reduce in an immense proportion the cost of 

 earthwork, bridges, and viaducts, even in parts of the country 

 where the character of the surface is least favourable. But the 

 chief source of economy has arisen from the structure of the line 

 itself. In many cases where the traffic is lightest, the rails consist 

 of flat bars of iron, two-and-a-half inches broad and six-tenths of 

 an inch thick, nailed and spiked to planks of timber laid longi- 

 tudinally on the road in parallel lines, so as to form what are 

 called continuous bearings. Some of the most profitable American 



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