The Jleigs Elevatea' Railway. —The system of Meigs Go/. 35, fig. 3), of which an experimental section is in operation in Boston, Massachusetts, is a great advance -upon the comparatively crude devices described on page 237. It is a single-post line designed for steam-traffic as a rapid-transit road in that city. The plan has a number of original and meritorious features. It differs from previous lines of its class in that it is a truck system, like the ordinary railway, and is capable of turning curves readily and of being operated at high speed with as Inuch assurance of safety as upon the ordinary railway. It has four rails instead of one, two, or three, as in those previously described, and the supporting wheels for the load are the lowest, thus insuring the greatest stability. The locomotive and cars are of cylindrical form, with rounded ends, and have other features of novelty. To demonstrate its practicability as a means of providing rapid transit, this system has been subjected to the most severe tests by a commission of engineers appointed by the city authorities of Boston, and has passed them very successfnlly.
Elevated a na' Una'ergrouna' Railways Compared. question of the relative merits of the elevated and underground systems as means of pro viding for rapid transit in large cities is at present attracting an unusual share of attention. A careful study of the subject will lead to the conclu sion that whenever a city has so greatly extended its area as to require for its future growth better facilities than those provided by the usual surface roads the underground railway affords the rational and ultimate solution of the problem.
The Elevated eminent American engineer, Professor Haupt, who has made the question of rapid transit in cities the snbject of special study, makes the following comparison: The structure of the ele vated railway must be in the air, and at a sufficient height to afford clear ance for surface-travel and to provide for the passage of extraordinary. objects; it must be between the heights of the second and third stories of the buildings alongside its route; its supports must extend into the streets, which they must obstruct to some extent. The operation of the road will be noisy—an objection that becomes very serious in summer, when doors and windows must be left open to secure ventilation. It will obstruct the light in the buildings and streets below its g,rade; it will afford no relief to the present surface-travel, so far as concerns the number of the vehicles and cars; and the structures could not, without extraordinary cost, be made attractive in appearance.
The Underground Railway. —The disadvantages of the underground railway are that it will require special provision for light, ventilation, and drainage, and that, to accommodate the rolling-stock of the road, it will have to be placed at least zo feet below the street-surface, thus debarring its patrons from seeing anything of the city from the train. On the other hand, it possesses the following distinct advantages, which are believed to be more than sufficient to counterbalance the disadvantages above enume rated: It is less noisy and would make less dirt than the elevated road, and would interpose no obstruction to light or to traffic. It could be made to
furnish a means of relieving the surface of much of its travel, would facili tate the handling of freight, would be more permanent and cost less to main tain, and would also confer upon the city the incidental benefits arising from having better pavements, requiring less expense to clean and maintain, and avoiding the necessity of continually breaking into them to lay or remove pipes, wires, and conduits, which has grown to be a serious evil.
It would give better drainage and provide the subways for all the city ser vice along its route, which no elevated road can do. It would have a speed sixty-six per cent. greater than that of the elevated road, and hence render about three times as much area available for habitation within the same time-limits. It would have much greater capacity, both because of its increased velocity and by having- four tracks iustead of two; and, finally, it could be made to pay an iudirect revenue of great value to the city.
Arcade Railway. —A proposition which has the approval of the municipal authorities of New York City is the so-called " arcade" railway under Broadway CA/. 37,.fig. 5). It contemplates the construction of what would practically be a second Broadway beneath the existing one. It is proposed to excavate this subway street with sidewalks at a general level of 12 feet beneath the street-surface, and between these sidewalks to construct a central roadway about 3 feet lower, to accommodate four rail wav-tracks, the two in the centre for fast trains, and the other two for slower trains for local traffic. The upper street is to be supported ou col umns and girders, with arches between. There are to be ample provisions for lighting and ventilation, and for the convenient disposition of sewers, of gas- and other mains. This plan—which, it is believed, will presently be carried into effect—would greatly lessen the overcrowding from which Broadway now suffers, and, besides, would afford the means of securing the rapid transportation of passeng-ers and merchandise.
The experience of New York, where the elevated system lias reached the limit of its usefulness, would seem to prove that some plan of under ground railway must soon be adopted adequately to meet the necessity for increased facilities which the surface and elevated roads are not able to afford. Figure 3 (pi. 37) exhibits another scheme of underground railway which has been proposed for the relief of the passenger traffic of the Amer ican metropolis.
Transil 1.1Y CiiieS.—The question of providing- means of rapid transportation over its entire area is properly regarded as the most import ant single question with which each large city has to deal. A period is reached in the extension of the built-up area of every city when the ordi nary surface-roads become inadepate to meet its necessities, and unless facilities are provided for more rapid transit its growth is checked; and, conversely, those cities (for example, London and New York) in which the provision for rapid transit has been promptly made as the necessity therefor became manifest have rapidly gained in population.