The Block System of Signaling on American Railroads; The Methods and Appliances Used in Manual and Automatic Block Signaling, Also Descriptions of Han

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1901 Excerpt: ...at the side of the track, holds a staff in a vertical position, from which an engineman can take it while he is passing at from 15 to 2") miles an hour. When a staff is taken out the horizontal arms of the crane automatically assume a vertical position. The action of the electric controlling devices shown in Fig. 503 is as follows: The operator having taken out a staff from his instrument unlocks lever No. 5, which works switch 5 and derailing switch 5. At the same time he closes, at 26, the circuit energizing the r,-ohm relay. He then pulls over lever No. 5, making a clear passage for the train from east to west on Track No. 1. and lakes out the staff. Taking out the staff opens the circuit at _0. but the rj-ohm relay is still energized, as a current flows through its coils, by way of the front point of the track, or 4-ohm relay. The slot circuit is now closed at 28. tThe slot, at L".l, must be energized to enable the operator to clear signal No. 7, for the train to proceed). After pulling lever No.,", the operator places the staff in the starti crane, and when in position it closes (at 27i the third and last point in the slot circuit, energizing it so that signal 7 can be cleared. Signal No. 7 being cleared, the circuit on the electric lock through the 9-ohm relay is broken, locking lever No. 5 in the reversed position, so that the switch cannot be moved until the train has passed over the short track section just ahead of the switch. The engineman of a train accepting the signal proceeds into the block section, and in passing the crane lat 27) takes the staff. The withdrawal of the staif opens the circuit on the electric slot, which puts signal No. 7 to the stop position automatically. The train also de-energizes the 4-ohm relay by passing...