Identification of Subway Track Irregularities Based on Detection Data of Portable Detector

Abstract

At present, the detection of subway track irregularities is mainly carried out by track inspection vehicles and track inspection trolleys. Such detections are restricted by subway service time, so they can only be carried out once every few months. This study explored the possibility of using the vibration of the vehicle body collected by a novel portable detector to detect track geometry irregularities. It makes a particular contribution to the dynamic detection of track conditions and the reduction of maintenance costs. Based on the data collected by the portable detector, wavelet transform was used to analyze the vibration of the vehicle body. The results confirmed that this method was effective in enhancing the correlation between vibration accelerations and track irregularities. Second, a data set processed by wavelet transform was resampled by a hybrid sampling method which uses clustering methods and considers data imbalance within each category. In this way, the imbalance ratio of the data set was found to be reduced without changing the original data set structure. Finally, the random forest algorithm and the gradient boost decision tree algorithm were adopted for classifying track regularity and irregularity data. The results showed that both two algorithms, especially the random forest algorithm, performed well for the longitudinal level track irregularity and the alignment track irregularity.

Heterogeneity‐oriented ensemble learning for rail monitoring based on vehicle‐body vibration

“…Special recognition and transformation algorithms were used to correct and match different batches of waveforms (mileage calibration) and synchronize them. These steps are based on previous studies (Liu, Wang, et al., 2022; Wang et al., 2022) and serve as the basis for this study. However, the waveform is still not guaranteed to be perfect.…”

Quantitative Detection of Vertical Track Irregularities under Non-Stationary Conditions with Variable Vehicle Speed

“…2 ⃝ Dynamic measurement-however, when the vehicles are running on the track, the enormous dynamic load can cause comprehensive elastic deformation of the rail, bed, and roadbed, called dynamic irregularity. Strictly speaking, compared with static irregularity, dynamic irregularity is more reflective of the actual vehicle working environment because it includes both the geometric irregularity before loading and track elastic deformation after loading [14][15][16]. Obviously, dynamic irregularity can not be obtained by direct measurement.…”