. Electric locking . erail is located. The control of the locks in these schemes is usually accom-plished through the medium of an indicator or repeater. This isdone in order to give visual indication of the condition of thetrack section and not compel the operator to depend upon watch-ing the train or trying his levers. Repeated trials will in timewear out the dog and the slot or segment of the lock. Fig. 86 illustrates scheme 1. The track relay A controlsthe indicator G, which in turn controls the lever locks for thederails and switches in track section A. The signal bus baris cut into as ma
. Electric locking . erail is located. The control of the locks in these schemes is usually accom-plished through the medium of an indicator or repeater. This isdone in order to give visual indication of the condition of thetrack section and not compel the operator to depend upon watch-ing the train or trying his levers. Repeated trials will in timewear out the dog and the slot or segment of the lock. Fig. 86 illustrates scheme 1. The track relay A controlsthe indicator G, which in turn controls the lever locks for thederails and switches in track section A. The signal bus baris cut into as many separate sections as are desirable for proper 90 SECTION LOCKING operation of the plant and the signal bus feed wire from theoperating switch board is broken through a normal contact on thescrew release to insure its being restored normal. be arranged so that the reversal of the screw release willcause the energization of the indicator, and in many cases thisarrangement will prove more Feeder for signalbus bar Scheme 2 is represented in Fig. 87. The switch bus bar is cutinto as man}- sections as there are track sections at the plant, eachbus bar section being controlled through a contact on the trackindicator and, if desired, through a closed point on the screw 5 fl-, Trr UU 5-» 0& Switch bus 5 iS Sivitch bus feeder Signal bus feeder FIG. 87. release. Thus, this arrangement accomplishes the same purposeas a lock on the lever because the dropping of the indicator -willcut current off from the switch, and while not permitting thepartial reversal of the lever when a train is on the track circuit,it will prevent the switch from being thrown, owing to the inter-ruption of the current supply. Lock Relays Versus Lever Locks. Opinions differ as towhich one of the schemes described offers the most are engineers who have taken the stand that locks on thelevers should always be used. Their reasons are numerous. 91 ELECTRIC LOCKING Cases h
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Keywords: ., bookcentury1900, bookdecade1910, bookidcu31, booksubjectrailroads
