184 RAILROAD solutely necessary for the traffic adds to the cost of construction and increases the dead weight of the rolling stock and the cost of working ; 3, that the dead weight of the trains is in direct proportion to the gauge on which they run ; 4, that a saving in first construction equal in many cases to 33 per cent, can be made by the adoption of the narrow gauge, which allows greater curvature, narrower banks, and lighter bridging, rails, and ties ; 5, that nar- row-gauge railroads have relatively greater traffic capacity than roads of the standard gauge ; and finally, that they are safer and can be more economically maintained and opera- ted. Narrow-gauge railroads have been built in many parts of the world. At the end of 1874 there were 2,025 m. in operation in the United States, 511 m. under construction, and about 6,000 m. more projected ; and in Canada 594 m. were in operation and 886 m. projected. The gauge of these roads is generally 8 ft., though that of the East Indian roads is 8 ft. 3J in. or one metre, and a few in other countries are 3 ft. 6 in. The rails weigh from 24 to 52 Ibs. per lineal yard. The engines, rolling stock, and other appurtenances are generally built after the same plans used by the roads of the standard gauge, but proportionally smaller. City Railroads. Although railroads were long used in Great Britain with horse power only, this method of working them was there generally abandoned ; but in the United States their peculiar adaptation for the streets of cities was early perceived, and they are now in use upon the principal thoroughfares of most of the cities. Cars seating from 22 to 50 passengers are easily drawn by two horses at the rate of 5 or 6 m. an hour, taking the place of a much larger number of om- nibuses, and running at considerably less ex- pense. The trucks turning upon pivots, the carriages turn round the corners of the streets without difficulty; and the rails being laid nearly flush with the surface, but little ob- struction is presented by them to the pas- sage of vehicles across the track. The im- portance and utility of this class of railroads having been fully demonstrated by their use in the United States, they have been introduced after much opposition into the principal cities of England, France, Belgium, Germany, and Spanish America. The metropolitan district railway of London is a double track road op- erated by steam, about 19 m. long, running through a tunnel with occasional open cuts, by a circular route from the Moorgate street station to the mansion house. It was opened in 1863, and cost about $3,500,000 a mile. Another quick transit railway in London runs from Charing Cross to the city terminus in Cannon street, and is carried on arches over the tops of the houses. It crosses the Thames twice near its termini, and carries an enor- mous number of passengers. The necessity for means of rapid transit is greater in New York than in almost any other large city, on account of its excessive length in proportion to its breadth, and the subject has bee a dis- cussed for many years. One of the plans most persistently urged was that of a viaduct railroad under Broadway, which required the excavation of the entire street, with provision for gas and water pipes, sewerage, and venti- lation, to be covered by a continuous arch sup- porting the surface roadway. A short experi- mental section of a proposed pneumatic rail- way was constructed under Broadway in 1870, and various other subterranean projects have been put forth ; but plans for elevated roads have met with the greatest favor. One such road, that of the " New York Elevated Rail- way Company," begun in 1866, has been in successful operation since 1872 from the Bat- tery along Greenwich street and 9th avenue to 80th street. It consists of a single track, carried by longitudinal wrought-iron girders resting on corbels supported by a single line of wrought-iron posts planted along the curb- stones. The original plan of operating it by stationary engines and endless wire ropes was abandoned for "dummy engines," each draw- ing three cars, adapted for 86 passengers each, at the rate of nearly 20 m. an hour. The "Gilbert Elevated Railway Company," char- tered in 1872, on the plan of Dr. R. II. Gilbert, propose to build a double track tubular road carried by a trussed iron bridge spanning the street, which is to be supported by a series of arches springing from wrought-iron piers resting upon stone foundations at the edges of the sidewalks. No complete system of rapid transit for the city seeming likely to be con- structed under existing circumstances, the le- gislature in 1875 provided for the appointment of a commission with full power to decide upon a general plan and devise means for car- rying it out. This body reported in October in favor of a double track elevated road on each side of the city, to be constructed by the two companies above named, or by another provisionally organized under the powers con- ferred upon the commission, called the " Man- hattan Railway Company." Considerable lat- itude is allowed as to details, but the whole system is to be completed by Dec. 1, 1878. Mountain Railroads. In 1865-'8 a railroad was constructed up Mont Cenis by the English engineer Fell, in which the traction of the en- gine is secured by two wheels working hori- zontally under heavy pressure against the sides of a middle rail. (See CENIS, MOXT.) In the railroad up Mt. Washington, New Hampshire, built in 1866-'9, the traction is effected by a cogged wheel working into a cogged rail firmly spiked to the track. The Mt. Rigi rail- way, in Switzerland, on the same plan, was completed in 1878. A mountain railway has been devised upon which the cars are carried astride of a single line of rails in turn sup- ported upon a line of posts ; but this plan has not yet been successfully applied. For the detailed statistics of railroads in the Uni-
