Track measurement

Turnout geometry measurement in motion

The efficient and detailed inspection of track condition is carried out since many decades using the track recording cars with instrumentation onboard that generates an efficient, quantitative statement of known track conditions. Their equipment changed with time, reflecting the new data collection systems available - from the purely mechanical contact systems to the contemporary non-contact systems with the real time computer measurement data analysis.

The state-of-the-art inspection cars are equipped with the on-board measurement and geographic reference data systems being the main and productive tool for safety inspectors. Measuring the track geometry provides information about their current condition, yet direct access to historical data is needed to make efficient detection of potential accident-causing hazards possible. However, no geometry car could take measurements of the turnout geometry so far, and usually the readings collected by the geometry cars passing the turnout zones were masked and not taken into account in the track assessment procedure, as they would reduce the track condition evaluation results. Therefore, the important permanent way elements - turnouts - highly affecting train operation safety, were not measured automatically so far, and the safety inspectors had to rely on manual measurements in selected characteristic points only. Yet - “a switch is a track" (J. Tiecken, Volker Rail), so its detailed measurements at points located as densely as possible along the turnout appears to be the novel approach to improvement of train operation safety. GRAW, Poland, responded to this need, developing in cooperation with Volker Rail (The Netherlands) and LAP GmbH (Germany) the self propelled inspection vehicle with the following systems:

• Optical laser measuring system for track and turnouts
• Navigation - Differential Global Positioning System (DGPS) to determine precisely location of turnouts, track defects and other reference points
• Visual track inspection