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.