Wakefield 99 Arches Viaduct Drone Survey

Project overview

Amco Giffen commissioned Infrastruct North Ltd (INL) to undertake a high-resolution LIDAR drone survey of the historic 99 Arches Viaduct in Wakefield, West Yorkshire. The objective was to support a wider condition assessment by providing an accurate, geo-referenced 3D dataset of the full viaduct structure, enabling engineers to analyse structural condition, deformation, and any potential maintenance requirements.

Given the complexity and scale of the structure, as well as its proximity to operational railway infrastructure, the project demanded rigorous planning, safety management, and precision data capture.

Scope of works

Operational planning and compliance

• Network Rail Air Operations were formally notified of the intended flight activity in close proximity to rail infrastructure.
• Detailed RAMS, including flight methodology and risk controls, were produced and approved.
• Safe take-off and landing zones were identified, considering public safety, rail operations, and site constraints.

Survey control establishment

• A network of ground control points (GCPs) was installed around the survey area.
• Control was established using Trimble total station and GNSS equipment, ensuring the LIDAR outputs were aligned to the required coordinate system and accuracy tolerances.

Aerial LIDAR data capture

• Data was acquired using the DJI Matrice 300 RTK integrated with the DJI Zenmuse L2 LIDAR sensor, providing dense and accurate laser point returns across the entire viaduct.
• Multiple flight paths were planned to ensure full coverage of the structure, including arch intrados and complex geometry.

Outcome and deliverables

All flights were completed safely and in accordance with rail-specific operational requirements. Following data collection:

• Raw flight data was processed within DJI Terra, applying trajectory optimisation, point cloud classification, and alignment to the established GCP network.
• A fully registered point cloud was produced in LAZ format and delivered to the client.
• A survey accuracy report was included, confirming vertical and horizontal tolerances achieved and validating the robustness of the dataset for engineering use.

The resulting high-fidelity point cloud now forms a critical resource for Amco-Giffen’s engineers, enabling detailed structural assessment without the need for extensive physical access or disruptive possession planning.