Mobile LiDAR and PTC

ptcMaser Consulting, a leader in the industry using Mobile Light Detection and Ranging (Mobile LiDAR), employs the use of Mobile LiDAR, 3D hi-definition laser scanners and other methods to assist in the implementation of PTC (positive train control). A PTC system must be able to reliably determine the precise location, direction and speed of trains; warn operators of potential issues; and automatically take immediate action to safely stop a train if an operator does not or cannot respond to the warning provided by the system.

Development and implementation of PTC has been a challenge for many reasons from the logistics of the initial physical survey in complex rail environments to the eventual coordination of the PTC infrastructure between the signal system, rolling stock and equipment, and operating departments within the freight- and passenger-rail networks. One of the primary tasks required includes the complete physical survey and precise geo-mapping of railroad right-of-way on which PTC technology is to be installed. Field assets extracted from the data include the track centerline for main line, siding and yard tracks; milepost markers; clearance points; curves; grade crossings; switches; retaining walls, bridges and tunnels; station platforms; and signals and associated equipment and apparatus, such as bungalows, cases, antenna towers and Wayside Interface Units (WIU) locations.

Mobile LiDAR is a proven remote sensing technology that is the perfect tool for mapping these assets. Maser Consulting’s survey team employs a Riegl VMX-450 Mobile Mapper, consisting of single or multiple laser scanners and high-resolution digital cameras. The scanning and imaging sensors are combined with specialized geo-positioning equipment mounted on, in this case, a hi-rail vehicle. The integration of these sensors and positioning instruments produces highly accurate 3D spatial models. Once collected, this data is processed and analyzed to suit a wide range of applications in a fraction of the time required by more conventional means. Using Mobile LiDAR systems, the team can quickly and accurately collect miles of rail corridor data for PTC and asset location mapping. Additional methods used for collecting the survey asset information needed for PTC include GPS, Mobile and Airborne LiDAR (or a fusion of all three), Ortho and oblique imagery, and conventional survey.

Maser Consulting’s survey teams also work and collaborate with other survey and signal engineering partners to provide hybrid LiDAR and imagery data for PTC. For example, they are currently providing QA/QC GIS Data Rail Asset Collection for CSX at various locations in Tennessee, New York, Maryland and Kentucky. The overall project involves the survey of rail assets including signals, rail crossings and switches. Our team collected data using Trimble Geo 7.x data collectors and were then responsible for differential correcting the .SSF files delivered from this data. Imagery of assets was linked to the geodatabase using the camera linkage application with the Trimble Geo 7.x. The data was then exported to the CSX geodatabase ESRI model for quality-control checking.

PTC is currently required to be installed and implemented on Class I and passenger intercity or commuter railroads with a mandated deadline of Dec. 31, 2018, under the H.R. 3819-Surface Transportation Act of 2015. Maser Consulting has made a commitment to the rail industry by actively growing their rail services to meet the needs of these specialized clients. By utilizing LIDAR, GPS and other geospatial technologies, they are assisting them in addressing the challenges to safely implement PTC as early as possible.

By Francis Miller III, PE, Director of Rail Engineering Services

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