As-Built Survey of Rail Corridor for Engineering Design

High resolution drone LiDAR, photogrammetry and as-built survey of rail corridor for geotechnical engineering design.


Diospatial was engaged to complete a survey of multiple sections of the rail corridor to support engineering design of geotechnical remediation works. Sydney Trains’ engineers required accurate bare earth terrain data, site visualisation and an as-built survey of the sites to support engineering design.

Project Scope
Drone LiDAR and Photogrammetry
Drone LiDAR and Photogrammetry
Feature Extraction
Feature Extraction

Diospatial developed an aerial survey solution which used drone LiDAR and photogrammetry to accurately scan and capture the sections of rail corridor, and then digitally extract features to create as-built drawings.

Aerial LiDAR was used to penetrate vegetation and capture the bare earth terrain data. A network of ground control points was established to ensure high accuracy. The LiDAR data was processed to produce a point cloud, which was then classified and further processed to produce Digital Terrain Model (DTM) and elevation contours. This was used to accurately mark out the crest and boundary of the rail corridor cutting for the as-built drawings.

The LiDAR point cloud and 3D reality model were both used to complete the scan-to-CAD workflow for engineering design.

Geolocated high quality images were captured and then processed in photogrammetry software to produce the high detail 3D reality model. This provided rich visualisation of the sites and was the basis for feature extraction. The linework was then compiled with the crest and boundary survey to complete the as-built drawings.

The client was provided with the as-built PDF drawings ready to be ingested in to CAD software for the geotechnical engineers to complete their designs. In addition to this, the client received all geospatial data in the specialist file formats, as well as hosted on a web based 3D GIS platform for easy viewing, sharing and collaboration across stakeholders on the project.

Field works were completed while trains were running with no personnel in the danger zone, and without any disruption to network operations.

The high detail geo-accurate 3D reality model provided rich visualisation of the site to provide context to the engineers working on their geotechnical designs. The reality model was provided to the client on a web based GIS platform which allowed them to virtual view the site in their own time, replacing assumptions with facts.


as-built survey of rail corridor using 3D reality model and feature extraction
The geo-accurate 3D reality model was used to accurately complete the feature extraction of the sites. This reduced time on site and allowed the client to complete their survey and inspection works remotely.
scan-to-CAD linework for as-built survey of rail corridor
Feature extraction was completed on the 3D reality model and LiDAR point cloud to capture all of the rail corridor components, crest and boundary lines. The linework was then provided to the client in both PDF drawings and within the 3D reality model.