Chap. XXX.
1577
a great objection to rapid movement, carriages passing over it being subject to a shock, toremedy -which inconvenience the rail is sometimes made to turn on a joint, so that thecarriages can pass in a straight line, those coming in an opposite direction opening theinner rail on one side, and shutting the other by their own pressure.
For the switches on the Liverpool and Manchester Railway , about 9 feet of the rail oneach side are moved on a cast-iron framing, securely bedded in the ground, or placed on
chairs made to re-ceive it: the move-able rails are unitedby an iron rod, andwork upon a jointat one end. A hori-zontal sheave is fi xedon a false centre,with an iron ringworking round it inthe manner of aneccentric, so thatwhen the handle at-tached to the verti-cal rod is turned itwill either open orshut the rail.
In another systempractised on this rail-way the rails areplaced upon a frameof cast-iron; two shortrails move on jointsat their ends, andwork to either sideupon it; they areunited by a bar ofiron, and when in oneposition the carriagespass by the continuedrails; when in theother they are di-
—r
111 “
r
Fig. 2964.
KILLINGWORTH RAILWAY.
Fig. 2965.
verted: these switches are moved in a similar manner to those already described on the samerailway.
The most usual plan is the crossing-rail: to prevent the wheels running off, the top ofthe rails is sunk below the surface, but the openings, where they cross, subject thewheels to a shock in their passage; the flanges are on the inside of the rails, and wherenarrowed out to a mere point, they are liable to change of form and to get out of order.
Engine for a double Plane. — The shaft which turns the machinery, fig. 2968., may bemoved by manual labour ; but where a steam-engine is employed, a crank will be neces-sary, or the shaft may be attached to a water-wheel. The cylinders upon which the rope