American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 613
ston. On the otherhand,when the piston falls, the air which is driven through the/^;Y hole also acts asa cushion, retarding the fall. The amount of tiiis air pressure is regulated by a valve.The lower end of the lever l moves in a closed chamber h. The opening throughwhich the lever l enters the… … halls railway signal. 503 Here p is the top of piston; w,w are the wires of the circuit, connecting with thecontact springs c,c. When the piston is raised it pushes the key k over so that thesprings, in this case, are brought together and the circuit completed. In the block track connections the…
Telegraph
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