File:The boys' book of railroads (1921) (14738108036).jpg

Identifier: boysbookofrailro00crum (find matches)
Title: The boys' book of railroads
Year: 1921 (1920s)
Authors: Crump, Irving, 1887-1979
Subjects: Railroads
Publisher: New York, Dodd, Mead and company
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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ontrol the air pressure at the switch,and by this pressure the switch is moved over orback as is necessary. In days gone by all this work was done bythe strength of a mans arm rather than theforce of compressed air (as was also true ofhand brakes on cars before the coming of thepresent-day air brakes). In those times theterminal tower, in fact all towers, had quite adifferent appearance. Instead of the tiny levers,there were batteries of huge hand levers, and asa switch was moved a man used all his strengthand braced his feet against the iron frameof the lever to help him in his effort. Thereare still many towers in which these great handlevers of the Manual type, as they were called,are used, but fortunately they are fast giving wayto the safer, swifter, and more accurate electric-pneumatic system. The rest of the tower equipment consists of aset of tiny semaphore signals set above the direct-ors head, but where he can see them withouteffort. One group of these tells him which of the
Text Appearing After Image:
An old type of switch tower where switches and signalsare turned by hand Inside the Terminal Tower where electricity does every-thing except the thinking THE MA2T IN THE TOWER 149 ten tracks in the train shed are clear and whichare being used, while the other tells hiin the con-dition of the signals on his four main tracks andother points in the yard. Outside on a bridge across the tracks are thereal semaphores that give the signals to the engi-neers. There are two signal arms to a track, onesuspended downward from the bridge andslightly smaller than the upper one. This, in theslang of the railroader, is the low ball andmeans when its arm is dropped that he can pro-ceed with caution. The upper arm or highball is the all clear signal, and when thisdrops the engineer knows that he has a cleartrack ahead. The normal position of both is at rightangles to the post supporting them and thisposition means danger. At night when theyare set at normal they show a red light whichalso calls out da

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