switch (swich)

[Formerly also swich; an a ibilated form of * swick, zwanken, bend.] 1. A small flexible twig or rod. Bell. Shall's to horse? here's a tickler; heigh, to horse! May. Come, switch and spurs! let's mount our chevals; merry, quoth a'. Dekker and Webster, Northward Ho, iv. 3. She had cut a willow switch in her morning's walk, almost as long as a boy's fishing-rod. Scott, Heart of Mid-Lothian, xxx i. 2. A mechanical device for shifting a moving body, or a current of electricity, etc., from one course or track to another. Specifically-(a) In railroads, in its simplest form, two parallel lengths of rails joined together by rods, pivoted at one end, and free to move at the other end, forming a part of the track at its junction with a branch or siding. The switch-rails rest on metal plates laid on the sleepers, and, by means of a rod fastened to their free ends, can be moved sidewise. The ends of the next pair of rails and the ends of the first pair of the siding or branch are placed side by side, so that by the movement of the switch either pair may be brought in line with the track, and any car or engine pa ing the switch will be guided upon the rails to which the switch is directed. Such a switch may be used to connect several lines of rails. The objection to this form of switch is that a car moving on a track not connected with the switch is liable to be derailed by running off the open ends of the track. This has led to the adoption of safety-switches of which there are various forms. One of the most common d. these is the split switch, in which the ends of the rails, instead of being square, are drawn out (split) to a thin edge so as to lie close against the side of the next rail. The narrow rails used are flexible and are fitted with springs, so that in the event of a displacement of the switch the lateral pre ure of the wheels will cause the points to move back and thus keep the wheels on the line, the points returning to their original position by the recoil of the springs. Another form of safety-switch is designed to keep unbroken the IMG:content-2649.png:[merged small][merged small][merged small][merged small][subsumed][merged small][subsumed][subsumed][subsumed][subsumed][merged small][merged small][subsumed][subsumed][ocr errors][ocr errors][merged small][subsumed][merged small][subsumed][subsumed][subsumed][subsumed][subsumed][merged small] Figs. 1 and 2. Point-switches, or Split Switches. Fig. 3. Stub-switch. Fig. 4. Double-slip Switch. Fig. 5. Section of fig. 1. a , a , main tracks; IMG:content-2650.jpg:[blocks in formation] grade is obtained by curving the track alter for shifting cars, making up trains, and other nately backward and forward along the side yard-work. It is usually a tank-engine, and is often car of the slope. Also called switchback railway. - ried without trucks on a rigid wheel-base, or has only a 2. By extension, an inclined railway in which pony-truck. the movement of a train or of a car is partly switching-eye (swich'ing-1), n. On a railroad, or wholly effected by gravity, as in the switch a cast-iron socket at the corner of a car, used IMG:content-2651.png:[graphic] back railway at Mauch Chunk, Pennsylvania, and railways constructed for purposes of amusement at watering-places, fairs, and pleasure resorts. In many of these the car first runs down a steep a le er incline, incline, and by its momentum is carried upa alternate ascents and descents being made till the end of the course is reached.