The construction of the Cambridge subway is nearly completed, and although no date has been fixed for the opening, it will probably be within the next month. The entire tube is now finished and the subterranean landing stages are ready for use, but there is still some work to be done upon the sections above ground. When work was begun upon this remarkable engineering project it was estimated that it would be nearly four years before it was completed. The Hugh Nawn Construction Company, in spite of two or three unlooked for delays has managed to bring the work almost to a finish in two years and three months.
For purposes of proper ventilation in the summer time the subway is built in two independent tubes instead of in a single double-tracked tube. On account of this method of construction, which is the same as that employed in the sub-aqueous tunnels near New York, the air is kept passing through the tunnels, and being constantly renewed, each train sucking after it a supply of good air and pushing out the stale air.
The track leading to Boston is on a level slightly lower than that of the outward bound track, in order to make it more convenient for passengers coming from Boston who wish to change cars for Arlington and Newton, and vice versa.
The large entrances and exits have been erected at Park street, Boston, and Harvard square. The one in Harvard square is especially large, as it was built to handle the exceptional crowds that attend the football games.
The line of the subway is through Brattle street to Murray street, where the "elevated trains," as the subway cars will be called, will ascend to the street. Surface cars from Newton and North Cambridge will enter the tubes at Cambridge common and Murray street respectively. Both tubes are so built that a platform two feet wide runs beside the tracks for the entire distance so that in case of accident or breakdown the passengers can walk to the nearest station without incurring any risk from electric wires.