It might almost be said that the new subways are built around the system of "piston" ventilation, instead of including a system of ventilation in the subway construction!
These ducts must prove in use to be little else than open sewers incapable of being flushed out, and in addition must admit surface waters into the bowels of the subway, with the extreme liability of causing costly and dangerous "short-circuits" to the power cables serving train propulsion, as occurred, recently four times in one day!
Contributary Gains
All the time, skill, labor, materials, defects and dangers involved in these constructions necessary for the "piston system" may be wholly saved by the adoption of the proposed "fan and air-lock" system!
In addition to these savings the "air locking," "piece-meal" system may be installed at any time, and in the minimum time, without even retarding a train or a passenger.
Since there is nothing whatsoever experimental about this system, and since all the results can be calculated in advance, and since its cost is certainly much below any plan suggested, it should apparently appeal to the City, the operators and the public.
On the ground of a "safety-first" system alone the method proposed seems to meet every requirement for quickly exhausting any smoke which might possibly be produced in the subways.
That the proposed system is a "safety-first" system, as well as adequate on the score of health, is almost self-evident when it is realized that, even if it were idle at the time of a fire, a single master electric switch at the power house could be instantly thrown into action, automatically or manually, thereby starting every fan at maximum capacity. This would insure, as has already been shown, the flushing out of "the entire cubic contents of the subway in ten minutes!" Incidentally the smoke, because it is heated, would naturally rise first to the roof of the subway and it is from this level that the fans would always be drawing the strongest.
Summary of Advantages
The advantages of this "sectionalized," "air-locking," system of electric-fan subway ventilation may be summed up as follows:
(1) Is calculable and results can be guaranteed in advance of installation.
(2) Is absolute in results sought.
(3) Is independent of all train movement.
