Northeast Illinois Positive Train Control (PTC) LiDAR

Metra | Northeast Illinois

Positive Train Control (PTC) improves railroad safety through automatic control of train speeds and movements should an operator fail to take appropriate actions. In northeast Illinois, Metra, who oversees all commuter rail operations in the 3,700 square-mile region, carried out engineering and geospatial projects to prepare its five commuter rail lines for PTC.

As a subconsultant, Merrick provided overall technical implementation, aviation coordination, LiDAR and camera sensor integration, surveying, LiDAR acquisition, point cloud post-processing, data fusion, and client geospatial training.

To collect a higher density of LiDAR data in the railroad right-of-way (ROW) and in areas not visible from the air such as tunnels and under bridges, Merrick created a customized data solution that combined LiDAR collected from both a helicopter and tack-mounted truck. The two data sets are then integrating using the same GPS positions. This unique method of combining airborne and hi-rail tack-mounted LiDAR allows continuous elevation and feature data to be collected throughout the ROW without any gaps or interruptions. All told, there were 380 miles of LiDAR created from the airborne platform and 12 miles of LiDAR using the truck.

Other sensors on the airborne platform include a set of oblique cameras, oriented fore and aft, and a nadir color digital camera. These additional sensors allow the photogrammetrist and engineer to accurately map, display, and analyze infrastructure and elevations within the railroad ROW. Combining these sensors on one helicopter facilitated collection of multiple data types during a single flying mission, thus saving the client money and time.

On completion of the project, Metra now has feature-rich elevation and rail asset data that can be used for PTC and many other uses.




2016 Geospatial Products & Services Excellence Award – Aiborne and Satellite Data Acquisition

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