Conventional surveying operations included setting and tying in 100 LiDAR targets throughout the project limits into the survey control network. All conventional survey operations were completed during day-time hours using a single 3-man field crew over 7 days.
The on-track hi-rail operations for the Mobile LiDAR data acquisition were completed in a combination of day and night shifts over 4 days where Amtrak provided +/-4 hours of track time per shift. The 3D feature extraction work started with extracting all the individual tracks at 10-foot intervals, including the “switch and frog” points. Point files for each track, main lines, storage, sidings and crossovers were created so that the design engineers could perform linear regression to define the track alignments and identify all the track “cardinal” points. The next phase of 3D extraction was focused on the OCS and Electric service overhead wires. 3D extraction work was complete with extracting out all the remaining visible planimetric and ground features to complete the 3D base mapping and DTM surface for the project.