Patent GB-1346651-A (GB)
Inventor: THEURER J
IPC: E01B35/06
Filed: 1971-07-02
Abstract: 1346651 Measuring railway track parameters F PLASSER 2 July 1971 [2 July 1970] 31044/71 Heading G1N In a self-propelled machine for determining the versine (lateral deviation from a desired position), joint position, twist, gauge and condition of the track bed of a railway track, the movements of various track-feeling wheels deform resilient members to which wire resistance strain gauges are cemented. The resilient members are made of spring steel and may be in the form of leaf springs Fig.2 and 3, (not shown) with two strain gauges (27) each side at the leaf root, or torsion bars of hollow circular or rectangular crosssection Figs. 4, 5, 8, 9 and 10, (not shown) with four strain gauges (27) midway between the ends of the bar oriented at 45 degrees to its longitudinal axis. The four strain gauges on each member are connected in a bridge circuit (Fig.7, not shown) in a manner to compensate for temperature variations and twist (of a leaf spring) or bending (of a torsion bar). The bridge circuits are balanced when the track is ideal. They are energised with stabilised alternating voltage and their outputs are amplified, filtered and fed to indicators, a recorder and a computer, or to control means for correcting the track alignment and tamping the ballast.  Versine. In Fig.11, three track-feeling axles 9a, one from each set 6, 6<SP>1</SP>, 6<SP>11</SP>, are hydraulically biased against one rail and the axles 9b against the other rail. Lateral movement of the axles in outer sets 6, 6<SP>11</SP> are mechanically coupled via rocker arms 10 and Bowden cables 42 to the free ends of leaf springs 18 carrying strain gauges 27. The sheaths of the Bowden cables are connected to the machine undercarriage 3 at their outer ends and, via rocker arms, to the intermediate axles at their inner ends, whereby lateral displacement of the intermediate axles is coupled to the leaf springs 18. Alternatively (Fig.11a, not shown) the sheaths of the Bowden cables may be fixed to the undercarriage at both ends, and the roots of the leaf springs mechanically coupled to the intermediate axles. Joints and condition of track bed. Relative vertical displacements between a load-bearing axle (2<SP>1</SP>, Fig.12, not shown) and feeler axles (6<SP>11</SP>) due to joints or bending of the track under load are mechanically coupled to leaf springs (18) via toggle levers (20, 24) and rods (43) to unbalance the associated bridge circuits. Twist. In Fig.13, track twist causes twisting of a torsion bar 28 connected at one end rigidly to a load-bearing axle 2<SP>1</SP> and at the other end, via a torsion-resistant linkage including a ball-andsocket joint 32 and plate springs 33 allowing relative vertical movement, to the intermediate feeler axles 6<SP>1</SP>. Alternatively (Fig.13, not shown) a leaf spring (18) may be rigidly connected at one end to one axle, the other end engaging a fork (46) connected to another axle, whereby track twists cause bending of the leaf spring and unbalance of the associated bridge circuit. Gauge. A leaf spring (18)(Fig.14, not shown) is rigidly attached at one end to an axle (9a) biased against one rail, the other end of the leaf spring engaging a fork (47) attached to an axle (9b) biased against the other rail, whereby deviation from the correct gauges causes bending of the leaf spring and unbalance of the associated bridge circuit. The feeler wheels are hydraulically raised off the rails during non-measuring transit of the machine.