Journal of the Association of Engineering Societies (1881)
Association of Engineering Societies (U.S.) · New York, [etc.] Board of Managers · leaf 224
will be two rings, with an interval between, while the danger signal will be. three rings so close together as to sound like one long ring. This makes the signal active both for safety and for danger, while if the apparatus is out of order that fact is indicated by the silence of the bell. Since… … By inspection of Fig. 4, we can see that with one connection F G and two insulation joints B and E we can so arrange a side track that if a car be standing too near the main track, that is, nearer than the point B, it will short-circuit the main track and give the danger signal. The system may be…
Engineering
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