The first subway planned in Boston was partly a two-track structure and partly a four tradc structure, and had a length of 1.7 miles. This has since been increased and the subway has also been connected with the elevated rail road system, so that at present both the elevated trains and trolley cars pass through it.
When these various railways were put under construction or in operation, the era of subway construction may be said to have become firmly established, and other lines were undertaken in Glasgow and Berlin, some of the shallow type and some of the tubular type, and elaborate and complex studies were being prepared for both Paris and New York. Although the work of beginning subway construction in these two last named cities had been retarded for one cause or another, the delay has nevertheless worked to their advantage, as the experience gained at other points had proved of great benefit. These two systems now present advanced and the highest development in the art of subway construction.
Work on the first line was begun in Paris In 1898. The French engineers, instead of doing as had been done elsewhere — laying out short and detached lines to serve the most urgent requirements and without regard as to the definite part that such lines would play in the final plan of urban development — laid out, at the beginning, a comprehensive map of a great system covering the whole of Paris, embracing all the lines that could reasonably be foreseen as necessary or desirable. This plan covers 47 miles of railway, all of which are considered as a unified system to be operated as a whole, and the construction of which has been steadily proceeding.
The work of building the subway in New York did not begin until the year 1900. In no city in the world are the demands for transit facilities as great as in New York. On account of the peculiar shape of the city the main travel is necessarily concentrated on a few well-estab lished north and south lines, and although great as is the carrying capacity of the elevated and surface systems, such capacity is much inferior to the demands of the population. At the time the first subways were opened the number of paying passengers on the street railroads of New York exceeded 1,000,000,000 per annum. It was decided to build a subway railroad with four instead of two tracks. Of these four tracks, two are used for express trains— that is, trains that stop at intervals of about one and one-half miles—and two of the tracks used for local trains, which stop at intervals of about one-quarter of a mile, in order to differentiate between the passenger who desires to travel a long distance and the one who desires to go a short one.
• The initial subway had a length of 20.8 miles, of which 6,3 miles are of four-track, 6.7 miles of three-track and 7.8 miles of two-track. This road begins at a point in front of the City Hall, extends northerly to Kingsbridge in the north western part of the city, and to the Zoological Gardens in Bronx Park in the northeastern part of the city, being in clan like the letter Y.
When this work was about half completed, a second subway was designed and contracted for to extend the above railroad southerly along Broadiway from the City Hall and under the East River to a point in the Borough of Brook lyn. This extension consists of 2.8 miles of two-track and 0.7 mile of three-track, making in all 24.3 miles in length, with 86.6 miles of track, exclusive of side tracks. Soon after this first subway was in full operation from At lantic and Flatbush Avenue Station in Brook lyn to Van Cortlandt Park on the west side and to Bronx Park on the east it was seen that additional transportation facilities would be required within a very few years. Negotiations to this end were initiated by the New York Public Service Commission with the Brooklyn Rapid Transit and the Interborough Rapid Transit in 1911 and on 19 March 1913 the so called dual contracts were signed by these companies on the one hand and the City of New York on the other. Under these con tracts the cost of construction was to be borne partly by the city and partly by the operating companies. The latter agreed also to extend
their elevated roads and to increase the facili ties of existing roads, by third tracking or by constructing a second story structure. The contracts called for the construction of 44.55 miles of new subways; 53.10 miles of new elevated railways, and 19.8 miles of third tracking or other additional track. The new lines, now practically completed, consist of 330 miles of single track, made up of 260 miles of subway, 45 miles of elevated and 25 miles of new third track, taken in connection with the old lines with their 330 miles of track, con stitute a mileage exceeding that of all the other rapid transit systems of the world. The year 1918 saw a number of the new lines included in the Dual System placed in operation, leaving to be finished those lines providing new routes between Brooklyn and Queens and Manhattan by tunnels underneath the East River. These tunnels are difficult engineering feats and re quire a longer time than does ordinary subway or elevated railroad construction. Subsequent to the completion of the first subway the city determined to build certain additional lines, in cluding the so-called tri-borough route in Man hattan and the Bronx ; the Centre Street Loop in Manhattan and the Fourth Avenue Subway in Brooklyn. All these lines later were in cluded in the Dual System. Of the Dual Sys tem subway lines, there were opened previous to 1918, exclusive of the first or old subway, the Queensboro Subway; the Fourth Avenue Sub way in Brooklyn; its 86th street extension; its Sea Beach branch to Coney Island; its New Utrecht avenue branch; the Astoria branch of the Queensboro Subway; the White Plains Road extension of the first subway; the Corona branch of the Queensboro Subway; the Jerome avenue branch of the Lexington Avenue Sub way; a portion of the Seventh Avenue Subway; the West Farms Subway connection, and the Broadway Subway, Manhattan. About 170 track miles of new lines were in operation at the beginning of 1918. On 1 July 1918 the new Seventh Avenue Subway was placed in partial operation from 33d street to South Ferry, and on 17 July the new Lexington Avenue Subway was placed in use from 42d street to 167th street in the Bronx. On 1 Aug. 1918 the so-called H system was tried. The beginning of this system terminated the service of the old subway as it had been riven for 14 years. Under the H system the old subway from Times square north with its branches was joined to the new Seventh Avenue Subway, thus constituting the west side subway, while the part of the old system south from 42d street and Fourth avenue was joined to the new Lexington avenue line and its Bronx branches, making a complete through line all on the east side from South Ferry to 167th street in the Bronx. This division of the old subway left the part under 42d street from Grand Central Station to Times square as cross-bar to the Its tracks were assigned as follows: Two tracks for a shuttle service between the east side and west side lines, and two tracks for a continuation of the Queensboro Subway west from Grand Central to Times square. Very serious delays in the work of construction of the new lines occurred in 1917-18, owing to the fact that the demands caused by war condi tions had been such as to delay the work, and in some respects to bring it to a halt. More subaqueous tunnel work is under construction for Dual System lines than has ever been at tempted before. This work represents an ex penditure of about $30,000,000, and includes four new tunnels of two tubes each and one tunnel of four tubes. The last named connects the Lexington avenue line in Manhattan with its Bronx branch. The other tunnels mentioned are the 60th street tunnel connecting the 59th Street Subway with the Queens line, the tunnel for the 14th street eastern line, the new borough tunnel between Manhattan and Brook lyn and the tunnel connection between the Broadway Subway • in Manhattan and the Fourth Avenue Subway in Brooklyn.