. Operation of trains and station work and telegraphy . crane ready for the train to take as it passes. Two opposing signals cannot be given at the same time,circuits of each being controlled by the other, making itnecessary for one of the two to be in the normal or firstposition, thus preventing confusion. The crane in use In this Installation is shown in Fig-ure 132. The a. B. C. System. The A. B. C. Rules on the Northern Pacific have passedthe experimental stage. is no longer a mat-ter of speculation. Apparently they have come to every viewpoint they are, without doubt
. Operation of trains and station work and telegraphy . crane ready for the train to take as it passes. Two opposing signals cannot be given at the same time,circuits of each being controlled by the other, making itnecessary for one of the two to be in the normal or firstposition, thus preventing confusion. The crane in use In this Installation is shown in Fig-ure 132. The a. B. C. System. The A. B. C. Rules on the Northern Pacific have passedthe experimental stage. is no longer a mat-ter of speculation. Apparently they have come to every viewpoint they are, without doubt, superiorto any single track system of rules and orders that haveyet been devised. They are now used on sixty-three milesof track, from Spokane tp RItzvIlle. On this territorythere are fifteen telegraph offices and three blind is all main line and handles a traffic so heavy that withthe ordinary system of train orders it was found impossi-ble to keep trains moving. STATION AND TRAIN WORK 419 p- 128 OHMS —*j640HMSl-320HMSl160HHSK-102 OHMS. The distance between two staff instruments depends upon trafficconditions and therefore the resistance of the line wire in series withthe line coil of the lock magnet varies considerably. The local coilof the lock magnet should have a variable resistance in series with itin order that it may balance perfectly with the line coil. This is ac-complished by using the adjustable resistance tube shown diagram-matically in Fig. 133. The table gives the required information for connecting up theadjustable resistance tube for any ordinary 1 represents the total resistance of the two line wires con-necting a pair of 2 shows the normal voltage reauired to operate. (This is50% above the minimum voltage required and gives a large work-ing margin.)Column 3 shows the corresponding number of dry cells required to secure the voltages shown in Column 4 shows the ohms resistance to be inserted in series
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroa, bookyear1919
