A methodology for the measurement of track geometry based on computer vision and inertial sensors

TL;DR

This paper presents a novel, compact, and low-cost computer vision and inertial sensor-based system for non-contact measurement of railway track geometry during train operation.

Contribution

It introduces a new methodology combining inertial sensors and video cameras for accurate, contactless track irregularity measurement suitable for installation on moving railway vehicles.

Findings

Capable of measuring multiple track irregularities including alignment and profile

Can be installed in various positions on railway vehicles

Operates effectively during train movement

Abstract

This document describes the theory used for the calculation of track geometric irregularities on a Track Geometry Measuring System (TGMS) to be installed in railway vehicles. The TGMS includes a computer for data acquisition and process, a set of sensors including an inertial measuring unit (IMU, 3D gyroscope and 3D accelerometer), two video cameras and an encoder. The main features of the proposed system are: 1. It is capable to measure track alignment, vertical profile, cross-level, gauge, twist and rail-head profile using non-contact technology. 2. It can be installed in line railway vehicles. It is compact and low cost. Provided that the equipment sees the rail heads when the vehicle is moving, it can be installed in any body of the vehicle: at the wheelsets level, above primary suspension (bogie frame) or above the secondary suspension (car body).