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. 1916 Excerpt: ... signals are square end, painted red with a white stripe; others with pointed end, painted yellow with a vertical black stripe or of same angle as the pointed end. Some distant signals have a notched end, painted yellow with a black stripe of the same angle as the notch. The pointed end semaphore is also used as a distant signal on some Railroads. Other Railroads use the square end semaphore as an absolute block signal and the pointed end semaphore as a permissive block signal. The latest single track block system is an absolute block signal governing departure at stations with the permissive block signal governing the arrival and the movement between stations. This system lacks the simplicity of the older system, but it has the merit that it permits trains to run closely together when moving in the same direction and holds opposing trains a station apart instead of holding them at the staggered signals between stations. Automatic signals, when practicable, are placed either over or upon the right of and adjoining the track upon which trains are governed by them. For less than three tracks, signals for trains in each direction may be on the same signal mast. On roads operated with the current of traffic to the left, the signals may be placed upon the left. Where tracks separate sufficiently to permit, the signals may be placed on the right of the track governed where the current of traffic is to the left. Block signals control the use of blocks, but unless otherwise provided, do not supersede the superiority of trains, nor dispense with the use or observance of other signals whenever and wherever they may be required. Interlocking signals, except dwarf or short arm signals coming within the block signal limits, may be made a part of the block signal system ...