Prototype inspection cart for detecting track geometry irregularities

Abstract

This article presents the design and construction of a ride-on geometry inspection vehicle that is controlled by a joystick to measure the width and cross-level height of a model railway track with a gauge of 459 millimeters. The vehicle utilizes a rotary encoder combined with springs, linear guides, and rolling wheels as a measurement tool for the rail width. An Inertial Measurement Unit (IMU) is used to measure the tilt angle between the railway tracks for calculating the cross-level height. To ensure measurement accuracy, the sensors were calibrated with instruments that have been calibrated in accordance with ISO/IEC 17025 standards. The rotary encoder has a measurement deviation of 0.1 millimeters, and the IMU has an angular deviation of 0.05 degrees. During testing, different speeds of 0.1, 0.3, and 0.5 meters per second were evaluated. The average width measurement deviations were found to be 0.10, 0.04, and 0.13 millimeters, while the average cross-level height deviations were 0.09, 0.56, and 0.44 millimeters, respectively. Subsequently, an analysis was conducted to compare the differences in the average error values of the width and cross-level height measurements of the railway tracks using Analysis of Variance (ANOVA). The measured rail gauge values showed no significant differences, while the measured cross-level heights indicated significant differences at the 0.05 statistical level. It was found that the average measurement error for the geometric cross-level height of the railway tracks at a speed of 0.1 meters per second was lower than that at speeds of 0.3 meters per second and 0.5 meters per second, with errors of 0.14 millimeters and 0.17 millimeters, respectively.