The development of a laser based system from LAP for onboard measurement of the turnout geometry is a breakthrough in the improvement of train operation safety. It allows for detailed measurements at points located densely along the turnouts. It improves the assessment of the turnout condition by cutting time between consecutive measurements and their analysis. By uploading results to the main database it facilitates data handling for use in track and turnouts improvements and repairs.

The efficient and detailed inspection of track condition is carried out since many decades using the track recording cars with instrumentation on-board 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. These state-of-the-art inspection cars are equipped with the onboard 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 permanent way element – 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” (Jacques Tiecken, VolkerRail), 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 LAP GmbH (Germany) and VolkerRail (The Netherlands) the self propelled inspection vehicle with optical laser measuring system, equipped also with the Differential Global Position System (DGPS) for precise location of turnouts, track defects and other points of reference.

The TMS system is capable to take measurements of track at speed up to 100 km/h every 3 m, and has the potential to reduce the measuring increment to 0.25 m. Its measuring speed in the turnout zone is 20 km/h with the measuring increment of 3 cm, as required by pertinent regulations. Rail types are automatically recognised, which makes it possible to evaluate their wear. Turnout types are read out from the GeoTEC database, as corresponding to the actual vehicle position. Turnout geometry condition is assessed according to the approach already in use in The Netherlands since 2002, implemented before in GRAW TEE-1435 track and turnout trolleys; moreover simulating now also measurement of profiles using the manual templates, as specified in regulations is possible.

The system switches automatically from its track- to turnout measurement mode based on GPS reading. All measurement data is stored in the on-board database, from which it is uploaded to the main GRAW GeoTEC database accessible to the maintenance engineers.

Nearly entire Dutch railway network definition is stored in GeoTEC system, so new measurement data can be automatically assigned to the track segments or turnouts identified by their geographical position. Remote access over GPRS/EDGE/UMTS to the vehicle’s measurement system supports remote software maintenance and/or access to the measurements currently carried out. The system operation is fully automatic, as it finds its location after turning power supply on and next it begins measurements switching between the measurement modes.

The system can generate measurement reports, lists of defects to repair, and verify quality of maintenance work carried out. Employment of the TMS system is a breakthrough in turnouts condition assessment cutting time between consecutive measurements, their analyses and upload their results to the main database for use in track and turnouts improvements and repairs.