High-speed, high-resolution laser scanners that monitor the clearance envelope of railroad tracks have been available to European and Asian companies for some time. Now, a rail track scanner has been introduced to North America that is designed to capture track geometry and track envelope data in one pass, creating a 3D point cloud. The product claims 3mm accuracy.
“The amount of time required on the track is decreased,” says Brian Daniel, North American regional manager for the Swiss-based Amberg Technologies. Daniels says that with old surveying methods, “one instrument is needed for alignment, another for height, and a third to check gauge and super elevation,” but the company's GRP System FX “does all this in one pass.”
One contractor, RailWorks Corp., New York, has been using the GRP to save time and money when surveying. “Before we did a lot of things by hand.” says Luis Nieves, superintendent for RailWorks Corp., New York, NY. “With this product we don't need a crew of surveyors every day.”
Amberg Technologies AG created the GRP System to be a modular platform used for many construction phases of a project, from as-built documentation to ongoing maintenance, says Daniels.
T.Y. Lin International's New York office is one of the first American consulting engineers to use the GRP device. The firm scanned the geometry of the track and tunnels to generate as-built drawings for design of the “Positive Train Control” systems for the PATH (Port Authority Trans-Hudson) service connecting New York and New Jersey.
Amberg Technologies combined several measurement techniques to create a 3D model that can, in real time, check the clearance envelope around moving trains.
“It saves both time and money,” says Nieves, which keeps him from going back to the site again for missed data. “Of course we're never really supposed to have to go back, but it's not a perfect world.”