Telegraph engineering : a manual for practicing telegraph engineers and engineering students (1922)
Hausmann, Erich, 1886- · New York : D. Van Nostrand Company · leaf 263
king machine is usually placed asclose as possible to the devices which it controls, butnumerous such machines are in use which are 6000 feet 248 TELEGRAPH ENGINEERING distant from some of the devices controlled. The use ofmechanical interlocking machines is restricted to shortdistances, say up to… … Fig. 18. operating switchboard and indicator groups, made by theGeneral Railway Signal Company. This machine has38 levers for operating switches and signals and has 14indicators. Such indicators are used for checking thecorrespondence of movement between the lever and thedevice which it operates,…
Telegraph
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