Study of Anomalous Characteristics Exhibiting Between Fixing Force of Switch and Tongue Rail Opening Force

Abstract

The tongue rail opening force of a turnout is measured to indirectly estimate the fixing force of a turnout. Although tongue rail opening force is known to be proportional to the fixing force, it is also known that the proportional relationship sometimes does not hold. This non-proportionality can lead to mis-estimation of the fixing force, in turn causing malfunction of the switch due to the high fixing force. In order to solve this problem, we clarified the mechanism and causes of the mis-estimation related to contact between rails. The results of field investigations and motion simulation using a flexible multibody model of switch, were used to developed maintenance methods and a measurement tool for avoiding mis-estimation. and a strong fixing force may also wear of parts in the point machine and the rods. Accordingly, it is important to adjust the fixing force to within a proper range. Figure 1 shows the fixing force action and related forces on the point machine and the rods including the switch adjuster and the switching bar. The internal locking mechanism of the electric point machine and the escapement crank in switching mechanisms for large turnouts, including high-speed rail turnouts, maintain a relative position against the stock rail because they are locked into position with fixing bolts and plates. The fixing force is affected by elasticity of the rods and tongue rail between both fixed ends, which are the switching bar in an electric point machine and the contact Earth retaining structures, such as bridge abutments and retaining walls, are con-structed at the boundary of bridges or embankments. There are a variety of earth retaining structure failure modes, therefore in order to be able to ensure rational aseismic reinforcement, it is necessary to develop a range of different aseismic reinforcement methods adapted to the relevant earth retaining structure’s failure mode. Moreover, there are many cases where construction work is severely restricted due to various limitations, such as land boundaries, available space, and time available for construction work. Therefore, the authors propose an aseismic reinforcement method, which can both improve seismic performance of earth retaining structures and be carried out efficiently. This paper outlines this research and describes some examples of the practical application of the newly developed reinforcement method.