Identifier: cyclopediaofappl05amer (find matches)
Title: Cyclopedia of applied electricity : a general reference work on direct-current generators and motors, storage batteries, electrochemistry, welding, electric wiring, meters, electric lighting, electric railways, power stations, switchboards, power transmission, alternating-current machinery, telegraphy, etc.
Year: 1916 (1910s)
Authors: American Technical Society
Subjects: Electric engineering
Publisher: Chicago : American Technical Society
Contributing Library: Northeastern University, Snell Library
Digitizing Sponsor: Northeastern University, Snell Library

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left inste-ad of to right <3Sshown, reverse /,e.3as J.3nd63iboth stations.Lightning arresters on signal wire should be spacedevery loooft These do not replace the others requiredfor the trolley wire Fig 214, Diagram of Automatic Block Signal System Hand-Operated. The simplest block signal used by electricroads is a hand-operated one constructed on the principle shown inthe diagram, Fig. 212. At each end of the block a bank of lamps is 325 228 ELECTRIC RAILWAYS located to indicate whether or not the block is clear. The lamps areplaced in a weatherproof box with a glass window. Red glass issometimes used to suggest danger. A double-throw switch is con-nected with the lamps at each terminal of the section, as shown inthe figure. The switches have no central position, the knife bladealways making contact with one or the other of the terminals shown.If the lamps are lighted, throwing either one of the switches will putthem out and if they are not burning, they will be lighted by throw-
Text Appearing After Image:
Fig. 215. Sit?nal Box—White DiskDisplayed Fiff. 216. Signal Box with FrontCover Down ing either one of the switches. A motorman on reaching a sectionof track, finding the lamps not burning, throws the switch. Lampsnow burn in each switch box and show that the section is in use.On arriving at the other terminal of the block the switch is thrown,extinguishing the lights and showing that the block is clear. Automatic. The crude arrangement described above is onlysuitable for use in roads with low-speed schedules. It fails to in-dicate in which direction the car in the block is going and it dependsupon the reliability of the train crews in operating it. An automatic 326 ELECTRIC RAILWAYS 229 system of some kind is, therefore, desirable if it meets the specifica-tions mentioned above. Figs. 213 and 214 show diagrammaticallyone of the simple systems which has been developed. The essentialfeatures of this are (1) a signal box with red and white lights, locatedat each end of a block, provid

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