Delivering a survey-grade, high-resolution 3D dataset using UAS photogrammetry and LiDAR to safely capture a complex, live rail corridor on the TFL network.
A UAS corridor survey was commissioned to capture a 4 km section of operational rail infrastructure on the TFL Network. The route runs through a dense urban environment and includes stations, platforms, bridges, trackside assets, retaining structures and constrained interfaces with surrounding infrastructure.
The requirement was for a corridor-wide, survey-grade 3D dataset that would enable confident engineering assessment and digital design, while keeping on-track access and operational disruption to an absolute minimum.
Surveying an active rail corridor presented a combination of technical, safety and logistical constraints:
A conventional ground-based approach would have required multiple possessions, extended access planning and increased safety risk.
A UAS photogrammetry and LiDAR survey was delivered using a fully integrated, survey-grade workflow tailored for live rail environments.
Using the TFL ‘Plant Approved’ operational status that Plowman Craven has gained through detailed safety analysis and documentation, our survey team conducted controlled flight operations alongside the operational railway. High-resolution nadir and oblique imagery was captured to enable continuous corridor coverage without the need for extended possessions or service disruption.
The approach combined aerial capture, survey control and processing within a single methodology:
This approach delivered a continuous, corridor-wide 3D dataset suitable for engineering assessment and digital design, while maintaining safe separation from live rail operations.
The UAS corridor survey delivered clear safety, programme and data-quality advantages.
Remote capture significantly reduced the need for surveyors to access the track environment, lowering exposure to live rail hazards
Parallel flight operations removed the requirement for extended possessions, allowing surveys to proceed without disrupting services.
Large sections of the corridor were surveyed rapidly, reducing programme risk and the need for repeat site visits.
High-resolution 3D datasets supported design development, clearance assessment and asset review.
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Interactive 3D data delivered through Plowman Craven’s Easl platform supported clearer communication and collaboration.
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The Acton Town to Alperton corridor survey demonstrates how UAS-enabled survey methodologies can transform the capture of complex, live rail environments.
By combining drone technology with rigorous survey control and rail-specific safety planning, a high-fidelity corridor-wide dataset was delivered with accuracy to ±15 mm. The data is suitable for engineering assessment, design development and visual inspection, while reducing programme risk and the need for repeat site access.
The project highlights how digitally enabled inspection and survey approaches can reduce on-track risk, protect live operations and provide reliable, design-ready data to support smarter infrastructure decisions.
