GB979067A - Method and apparatus for reducing irregularities in a surface - Google Patents

Abstract

979,067. Track levelling apparatus. RAILWAY MAINTENANCE CORPORATION. May 9, 1961[ May 31, 1960], No. 16794/61. Heading B7N. Apparatus for levelling railway tracks comprises a lifting and packing machine 40 and two elongated beams 41, 42 which extend forwardly between the machine and a first cart 43 and between the first cart and a second cart 44, respectively. A sensing device 45 connects one end of the first beam to the machine and a similar device 46 connects its other end to beam 42. Each sensing device, e.g. 46, includes stub beam assemblies 82, 83 which are connected to beams 41, 42 by detachable vertical pivot arrangements 48, 49, respec. tively, and to each other by a horizontal pivot pin 81. The upper part of each stub beam is connected via a scissors mechanism to a potentiometer whose tap position varies with the degree of pivoting of the beams about pivot 81. The beams are supported on the carts at an adjustable height above the track by means of mounting brackets 74. Potentiometers R1, R2 associated with sensing devices 45 and 46, respectively, are connected in parallel in a bridge circuit which includes fixed arms R6, R7 and a galvanometer G. Before use the apparatus is positioned on a known level part of the track and the potentiometers are each adjusted in turn, with the other isolated by a switch S1 or S2, to give zero reading on the galvanometer. In use the rear wheels of the packing machine are positioned on a corrected portion of track and where cart 43 is above cart 44, Fig. 3A, the potentiometer of the sensing device 46 is prevented from acting in the circuit by rectifier D3 and the front of machine 40 and the track beneath it are lifted until angle #1, as measured by the potentiometer of sensing device 45, is zero. Where cart 44 is above cart 43, the front of the packing machine and the track beneath it are raised until #1 equals ¢ #2, this condition produces a zero balance in the galvanometer since R4, which is in series with the potentiometer tap of sensing device 45, is half the value of R5 which is in series with the potentiometer tap of sensing device 46. In each case the track below the front of the machine is raised into line with a high point in advance of the machine.