Spain-based Sigma-Rail aims to reduce the number of people accessing rail corridors for different construction, maintenance and operational tasks. Recently, the service provider of capture, processing and visualisation of railway infrastructure data completed the full 3D modelling of a future high-speed line between Rabat and Casablanca in Morocco.
Digitalizing a rail corridor using mobile mapping and mining data from 3D point clouds is a first-of-its-kind project in the MENA region, introducing a host of cutting-edge technologies for the region’s infrastructure business.
The project led by Bombardier Transportation consists of the installation of new interlocking and signalling systems based on the European Railway Traffic Management System (ERTMS) standards to cope for high-speed traffic.
To execute the project, Sigma-Rail mounted a mobile mapping device from its partner Leica on a maintenance rail vehicle. The vehicle ran the length of the line at night during the maintenance working window and captured the entire line in four nights, despite the tightness of the maintenance window due to the heavy-traffic on the line.
Mobile mapping is a technique that involves collection of geospatial data from a moving vehicle. In this case, a LIDAR together with an accurate GNSS receiver and an inertial measuring unit (IMU) were mounted on the maintenance vehicle. The pulsing laser used in the LIDAR device can reach more than 100m at each side of the vehicle, generating a complete 3D point cloud of the corridor and its surroundings. To obtain the model with higher accuracy, the 3D point cloud is adjusted during post processing by using ground control points (GCP) gathered using topographic-grade GNSS receivers on the track and then matching those points of known locations with point clouds.
Once the data is acquired using the mobile mapper, the 3D point clouds are post-processed at the office. Data such as the number of signals, boxes, and track circuits as well as their accurate kilometric point (milestone) are mined from the point cloud and formatted according to the client’s requirements. In this manner, a full geo-located stocktaking of the rail corridor is possible within days after the capture is carried out, avoiding hundreds of man-hours on the track.
Jorge Lopez-Sanchez, managing director, Sigma-Rail, says: “This method reduces the risk of personnel entering the track and potential human errors. This is critical on a heavy-traffic line such as Rabat-Casablanca which handles both passenger and freight services and where an ERTMS Level 1 is being implemented. The ERTMS system requires geographical location accuracy for safety-critical related assets. It was also possible to mine the track slopes from the 3D point cloud, as there was accurate information about the height of each point cloud. This way, it was possible to automate the gradient calculation extracted at the frequency required by the client.”
Sigma-Rail also performed a complete analysis of the elements installed on the track, which helped simplify contracts with the companies handling the works on the tracks. It helped reduce project risks before the testing phase.
“A deeper analysis is possible once the data is extracted from the 3D model. For instance, a human factor analysis regarding the new indication point to the driver on the ERTMS braking curves can be carried out to study the potential impact on current driving practices of the deployment of ERTMS. The information can be also used for training and operational readiness purposes, all of which can be done before the testing and commissioning phase of the project,” says Lopez-Sanchez.
