Permanent way rolling stock and technical working of railways Volume 1; Followed by an appendix on works of art

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. 1877 Excerpt: ...the limit, In practice the height, which is variable, of the centre of gravity above the centre lines, the suspension springs, and the elasticity of the substance of the wheels and of the blocks, modify the data of the problem. Besides the only object here is to give a summary idea of the action of these blocks; experience ought to determine their actual height. »30. These stop-blocks may be differently arranged. In England, for instance they are generally composed of a block of wood, working round an upright pivot, or on a horizontal hinge, which turns down upon one of the rails and butts against an iron pin. The block acts therefore upon one only of each pair of wheels; it stands up usually from three to five inches, and sometimes as much as ten. In France preference is given to the model adopted first on the Lyons Railway (PI. XIII, figs. '29 to 33, also 25 to 28). It consists of a wooden frame fixed to a sleeper by two hinges; when down the side c, equal in length, excepting the small amount of clearance necessary, to the working width betwee'n the rails, lies between them and below the bottom of the wheel-flanges; when raised it rests against two long prop-bars t, t, and its two extremities, shod with an iron plate, prevent the further progress of the flanges: the block stands up from ten to eleven inches above the rail-level, which appears amply sufficient. Even ifthe first pair of wheels should gel over the block, the second ones would be brought up by it, in consecruence of the loss of velocity due to the first concussion; it is absolutely necessary however, that the block should be constructed of sufficient solidity to resist the concussions, which is not always the case. In Germany on some railways, the waggon is moored to the line by one of ...