Estimation of track parameters and wheel–rail combined roughness from rail vibration

Abstract

Rolling noise from railways is significantly affected by the wheel-rail combined roughness and the dynamic properties of the track. To facilitate vibration and noise predictions it is desirable to be able to determine these parameters accurately from field measurements. In this study an inverse method to determine these parameters is adopted and enhanced. Use is made of a track model based on a wavenumber finite element model of the free rail coupled to discrete supports, which allows for the pinned-pinned mode and cross-sectional deformation of the rail. The rail vibration induced by hammer impacts and the vibration during train passages are simulated using this model, and these results are then applied to illustrate the accuracy of the direct and indirect methods for the estimation of track decay rate. These methods are compared in a case study for a ballasted track for which hammer impact and train pass-by measurements have been obtained. Other track parameters can also be extracted from the measured data by using the advanced track model. Thereafter a more complete method is adopted to estimate the wheel-rail combined roughness from measured rail vibration under train passages. A comparison is conducted among the estimated roughness levels obtained from this full method, an existing simplified method and the direct measurement method. It is found that the simplified method overestimates the roughness around the pinned-pinned resonance frequency but gives a good estimation if the track decay

Experimental Investigation on the Wear and Damage Characteristics of Machined Wheel/Rail Materials under Dry Rolling-Sliding Condition

“…Nevertheless, very few systematic investigations concentrating on the rolling-sliding wear and damage characteristics on the wheel/rail materials after machining can be available, which means that the effect of surface integrity of the machined wheel/rail materials on adhesion coefficient, wear and surface damage lacks sufficient systematic investigations. Existing studies pertaining to the surface integrity of wheel/rail interface have primarily centered on railway environmental noise [21][22][23]. In fact, surface integrity of the machined workpiece plays a crucial role in affecting the tribological performance during the rolling-sliding process.…”

Dynamic interaction of the low-to-medium speed maglev train and bridges with different deflection ratios: Experimental and numerical analyses

“…There are currently many effective test methods for the track irregularities of the traditional wheel–rail transit (Li et al, 2018a). However, the maglev transit is novel transportation, and the maglev track is different from traditional wheel–rail transit track structure; hence, the tested track random irregularities of the LMS maglev line are still scarce at present.…”

The influence of variation in track level and support system stiffness over longer lengths of track for track performance and vehicle track interaction

“…The simulations were based on a six-vehicle train with the suspension characteristics and car body, bogie and wheel masses of the Class 395 Javelin [62], for which about half of the measurements were made. The vehicle parameters used are given in Table 2.…”