WSP’s project team, consisting of specialists in geomatics, system development, and railways, have together developed a method and process for accurate and collection of assets in and around the whole track environment which was fed into an asset database where every object is classified, documented and georeferenced. An essential part of the method involves a data capture and mapping technique using both laser point cloud and 360-degree images.
To facilitate functional planning for this project, the railway was surveyed using mobile mapping techniques developed by WSP. The system used for this project has evolved from Mobile Mapping Geotracker™, a road based mapping system that has been in operation for over a decade. This unique method of quickly gathering information along railways is called ‘on-track-scanning’ and uses a specially adapted and outfitted “on-track vehicle”.
The rail vehicle is additionally fitted with industrial Gocator-scanners for tracks. The Gocator scanners are high speed and able to scan in extremely high detail. This arrangement enables WSP to detect defects down to millimeter accuracy; effectively covering everyday maintenance issues and limiting traditional inspections to defects testing only. The additional scanner setup enables track gauge measurements and track height differences.
Data Visualization and Management
All the information required to populate the asset management database is extracted from the captured point clouds and images. There are two great advantages and benefits to this method: the laser point cloud enables a precise measurement of position, and the easy to use 360-degree image viewer helps quickly recognize and identify the objects.
The 360-degree images and laser data can even be published for specific user groups or stakeholders. Then users via Railview (Maximo and an integrated Orbit 3D-viewer) are able to navigate virtually the whole railway network and see information visually as they go. The system is especially useful, and possibly essential, for many projects that involve maintenance, refurbishment or completely new construction of facilities. It allows users to obtain information about any part of the railway infrastructure directly through their web browser.
As part of the project, we developed the cartographic application Railview. Railview is an interactive exploration and asset querying tool for a wider user group in the Stockholm public transport administration. It allows searching for and through asset information, visualizing it via a map, 360-degree images or a data table. Simplified filtering options are included to ease content and data exploration, for example by railway line, discipline/technical area, geographic position/zone or even free text.
Clearance Profile and Clash-Detection Assessment
The GeoTracker system used to collect spatial data in this project includes sensors designed to provide information required for additional types of analysis. For example, it is possible to evaluate the cross-sectional clearance profile at regular intervals along the track and identify objects that are too close to the track and could be dangerous to passing trains. The method is based on laser scanned railway profile measurements used in conjunction with an ocular inspection of 360 degree imagery.
The analysis is undertaken in 1m intervals. All laser scan points in the preceding meter are included in the analysis. Every cross-section includes information in accordance with the client’s infrastructure model including, but not limited to, line, section, track number and mileage. All points within the clearance profile are detected and marked in red and used to support the planning future track side maintenance operations and removal of objects within the clearance profile. Beyond the mileage and location-specific information, the output also quantifies the number of clash points and highlights them visually.
Every potentially dangerous zone or object can be viewed in the 360-degree images via Orbit and even measured in the viewer via the measurement tool. This technology and methodology are the fastest means of analyzing entire rail environment and assessing the surrounding environment.
Contact Wire Position Statistics
Contact wire positioning is achieved through high accuracy line and LiDAR scanners. These are used to detect and establish a rail top surface (providing the track centreline) and LiDAR scanners to detect the contact wire. As a result, statistical data displays the offset and evaluates the difference in the overhead contact wire position in X, Y & Z axis. In the viewer it is possible to snap from the contact wire to point in the point cloud.