Numerical Testing of Switch Point Dynamics—A Curved Beam with a Variable Cross-Section

Abstract

The article presents mathematical considerations on the dynamics of the springing switch point being an element of the railway junction. Due to the structure of the switch point, mathematical analysis was divided into two stages: The first stage refers to the analysis of the dynamics of the switch point as a beam of variable rectilinear stiffness to which three forces (coming from three closures of switch drives) placed in the initial section of the switch point are applied. The next stage of the analysis concerns an identical beam, but curved, with a variable cross-section. In both cases, the beam is subjected to a vertical force resulting from forces from the rail vehicle. The calculations refer to a switch point of 23 m length and a curvature radius R = 1200 m. The first stage of the switch point analysis refers to the movement of a rail vehicle on a straight track, and the second stage concerns the rail vehicle movement on a reverse path. This article also provides an analysis of mode vibrations of a curved beam with a variable cross-section, and variable inertia and stiffness moments (further in the article the changes will be referred to as beam parameter changes). It is assumed that the beam is loaded with vertical forces (coming) from a rail vehicle. The solution was found by applying the Ritz method, which served to present the fourth-order partial equations as ordinary differential ones. The numerical research whose results are given aimed to define how the changes in beam parameters and vertical load affect mode vibrations of the beam.

Mechanical Wear Contact between the Wheel and Rail on a Turnout with Variable Stiffness

“…Next, we proceeded to determine the wear on the wheel and rail. Two works, [12] and [13], were used to consider this topic. Based on them, the following relations can be written:…”

“…Motion without a turnout and motion through a turnout were considered with track susceptibility (elasticity and viscous damping) as constant. According to the research conducted in [12], there are significant differences in the appearing vertical forces and normal forces when passing through a turnout with different values of the beam-subtrack system susceptibility. These forces affect the process of phenomena in wheel-rail contact and have an impact on the wear in the wheel-rail pair.…”

Railroad Turnout Wear Diagnostics

“…The turnouts used in Poland are mostly characterized by the circular curve of the turning track axis. The description of these designs and the way of shaping them in the track system is described in [ 70 ].…”

“…Turnout diagnostics include [ 70 ]: Visual inspection conducted visually in order to determine if there are any cracked, chipped or damaged parts in the turnout as well as other defects or deformations that may affect the proper operation of the turnout; Technical tests (inspections), which include: Visual inspection of the turnout; Assessment of technical condition of all structural parts and geometric layout; Assessment of correctness of operation of moving parts. …”

“… Measurement scheme of width and grooves of the turnout [ 1 ]: in the pre-spire contact a, in the firing pin blade b, in the firing pin seat c, in the middle of the turnout d, before the throat s, in the cross member e, and the distance of the leading edge of the steering wheel from the closer edge of the bow f and the width of the groove in the firing pin socket g, at the steering wheel h, in the cross member i, in the throat g, in the firing pin housing z. [ 70 ]. …”