Wiring diagrams of electrical apparatus and installations (1913)
McGraw-Hill · New York, McGraw-Hill Book Company · leaf 254
Fig. 402. … Transmmcorr hne Fig. 403.—Signal system for double-track electric road. 25-cycle e.m.f. is impressed uponthe transmission system which extends along the track. The track sections are connected tothe line through transformers. In order not to interfere with the use of the track as returncircuit for…
Electric wiring
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