. The Street railway journal . FIG. 104. than the head of the rail, and with its broader bearingagainst the back of the inside wheel flange, prevents de-railment. There aie many who think that curves fromabout 100 ft. radius down should have a guard on theouter or long side as well, on the ground that the rearwheels have a tendency to run off on the inside of thecurve. There is such a tendency, but it is so slight and sonearly overcome b) other forces that it does not require theservices of an outer guard to keep them on. An experi-ence with several thousand curves built with single guardand u
. The Street railway journal . FIG. 104. than the head of the rail, and with its broader bearingagainst the back of the inside wheel flange, prevents de-railment. There aie many who think that curves fromabout 100 ft. radius down should have a guard on theouter or long side as well, on the ground that the rearwheels have a tendency to run off on the inside of thecurve. There is such a tendency, but it is so slight and sonearly overcome b) other forces that it does not require theservices of an outer guard to keep them on. An experi-ence with several thousand curves built with single guardand used by cars of all conditions and gauges has tended. FIG. 105, to confirm this latter proposition. There are two decidedbenefits to be derived from the use of but one guard,namely, a saving in first cost of the curve, and a continualsaving in power required to move cars around the curve,due to an avoidance of additional flange friction. Fig. 104 shows very clearly the position a rigidfour wheel truck assumes in traversing a curve. Theshaded portion of each flange represents that which is be-low the top of the head of the rail, and the black portionof same the part of the flange in contact with the rail, thearrow indicating the direction of travel. The truck isguided almost entirely by the inner front wheel (i) andthe flange of its mate (2) is in contact onl} when thegauge of track and truck permit. Wellington shows thatwhen not restrained l^y the flanges, the rear pair of wheelswill follow the forward pair in the manner shown in Fig. 105, i. e., with the rear axle on a radial line. On a 35 curve the distance of the rear wheels
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
