The pier longitudinal horizontal stiffness is the key technical parameter of rigid frame bridge and the continuous welded rail. Both the distribution of longitudinal force and the relative displacement between the beam and rail are rely on the longitudinal horizontal stiffness of the pier. This passage takes the symmetrical arrangement of different span rigid frame bridge in ballast track as an example to study the value of pier top longitudinal horizontal rigidity, using the finite element method. The analysis show that when the amplitude of rail temperature variation is less than 50 °C and the nominal temperature span within a certain range, the minimum value of pier longitudinal horizontal rigidity depends largely on the braking conditions. However, as the further increasing of the span, the pier longitudinal horizontal rigidity is restricted by the expansion conditions. Therefore, the small resistance fastening system should be taken into consideration. Especially, if the temperature of rail reaches above 50°C, laying rail expansion adjuster is needed in order to satisfy the requirement of the continuous welded rail temperature on bridge.

Switching force and inadequate displacement are two key issues in the conversion of switch rail, which determined some important parameters such as the traction position of switch machine, the displacement of traction point and the length of switch rail. This paper taking the NO.9 turnout of 60kg/m rail in a line of Wuhan rail transit as the research object, using the open architecture of ANSYS software and its secondary development, establishing the calculation procedure of switching force, calculating and studying the influence of switch force and inadequate displacement of switch rail by the stiffness, the number of fastener groups and the friction coefficient of sliding bed on the heel of switch rail.

Pavement roughness is an important index to reflect the quality of pavement. To improve the efficiency of pavement roughness measurement, a novel pavement roughness measurement system based on structured light vision inspection is proposed in this paper. By describing the principle of structured light inspection and measurement system design, it is stressed that the proposed system can be used to acquire a continuous longitudinal profile of pavement and International Roughness Index by using the structured light illumination and CCD. Some experiments are performed to test orientation precision and performance of the system. The experimental results show that the system has some pros such as high orientation precision, good stability and low cost.

Because of the complexity of turnout, the wheel-rail contact of turnout region is more complex than that of railway line. In order to study the wheel-rail contact Geometry relationship of turnout region, using cubic spline interpolation method to get the outline of control sections, the ideal wheel-rail contact relationship in turnout region was obtained by the means of trace line, and then analyze the effect of track-distance roughness on the dynamic wheel-rail Geometry contact, the result shows that appropriate gauge widening can improve the structure irregularity.