Laboratory Evaluation of Railroad Crosslevel Tilt Sensing Using Electrical Time Domain Reflectometry.

Sijia Li,Kenneth J Loh,Chi-Lin Chen

doi:10.3390/s20164470

Abstract

Crosslevel is defined as the difference in elevation between the top surface of two railroad tracks. Severe changes in crosslevel, for example, due to earthquakes, ground settlement, or crushed ballasts, affect track geometry and can cause train derailment. Therefore, the objective of this study was to monitoring railroad crosslevel by using electrical time domain reflectometry (ETDR) to simultaneously interrogate multiple capacitive tilt sensor prototypes connected in a transmission line. ETDR works by propagating an electrical pulse signal from one end of the transmission line and then monitoring the characteristics of each reflected pulse, which is affected by the capacitance (or tilt) of the sensors. This study begins with a discussion of the capacitive tilt sensor’s design. These 3D-printed sensors were tested to characterize their tilt sensing performance. Then, multiple tilt sensors were connected in a transmission line and interrogated by ETDR. The ability to use ETDR to multiplex and interrogate sensors subjected to different angles of tilt was validated.

Highlights

In the United States (US) and around the world, railroads are commonly used for transporting goods and people across distant locations
Each data point corresponds to the average change in capacitance, while the error bars are the standard deviations of repeated measurements
These results indicated that the intensity of the peak voltage of the reflected wave increased in tandem with increasing angles of tilt and the sensor’s capacitance

Summary

Introduction

In the United States (US) and around the world, railroads are commonly used for transporting goods and people across distant locations. According to the US Department of Transportation, the freight rail network in the US is considered one of the most dynamic systems in the world [1]. It is a $60 billion industry with 140,000 miles of rail tracks, 21 regional railroads, and 510 local railroads [2]. In 2019 alone, there were 1848 train accidents in the US according to the US Federal Railroad Administration, of which 1283 were derailments [3]. A notable railroad catastrophe was the derailment that occurred in Washington DC on 18 December 2017

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Conclusion