Case Study | Colas Rail and West Midlands Metro - Birmingham Eastside Metro Extension
Turning Utility Strikes into Subsurface Certainty
Colas Rail brought in Exodigo after multiple utility strikes disrupted construction on the Birmingham Eastside Metro Extension. Across three congested urban sites, Exodigo delivered a verified PAS 128 utility map that revealed dozens of uncharted lines, corrected unreliable records, and gave crews a safer path to excavation.
- 3congested urban sites scanned
- 208utilities detected
- 51uncharted utilities found
- 136lines with verified depth
Project Summary
Mapping three strike-prone sites in dense urban ground.
Colas Rail engaged Exodigo to conduct non-intrusive subsurface utility mapping across three Birmingham sites along the Eastside Metro Extension for West Midlands Metro. The project had already experienced several utility strikes, and existing statutory records, utility records, and PAS Level A/B as-builts had proven unreliable.
Exodigo reviewed the available records, scanned the sites with its multi-sensor ExoCart platform, and delivered a Composite Utility Map that gave Colas Rail a verified picture of underground conditions before further excavation.
THE CHALLENGE
Unreliable records on an active metro build.
Unreliable existing records
Statutory and utility records and the PAS Level A and B as-builts from conventional surveyors couldn't be trusted to reflect what was actually in the ground.
Strikes already on the project
Colas Rail had encountered several utility strikes during construction, each carrying risk of injury, work stoppage, and change orders.
Congested, long-developed ground
Three dense urban sites layered with decades of infrastructure left little margin for an unseen line.
Limits of conventional methods
Traditional locating couldn't deliver complete coverage or dependable depth across the corridor, particularly at this density.
Exodigo's Approach
Verified mapping for safer excavation.
Exodigo combined remote record review, non-intrusive multi-sensor scanning, and high-density data collection to produce a single defensible utility dataset that Colas Rail could plan and excavate against.
ExoInfo
Remote Data Collection & Integration
Exodigo reviewed and reconciled the available record set — statutory and utility records together with the PAS Level A and B as-built maps — flagging discrepancies and prioritizing the three sites before any fieldwork began.
Utility Mapping
Non-Intrusive On-Site Reality Capture
Across the three congested Birmingham sites, Exodigo conducted non-intrusive multi-sensor scanning using ExoCart, capturing both conductive and non-conductive utilities without any ground disturbance to active works. High-density data collection — roughly 20 GPS measurements per second, about 30× the sampling rate of conventional locating — resolved line geometry, curves, and depth that traditional methods routinely miss. Exodigo delivered a Composite Utility Map produced to a PAS 128 Type B survey, with each detected line identified to PAS 128 Quality Level B1P, in ESRI ArcGIS (map package / ArcGIS Online), AutoCAD, KML, and PNG formats, referenced to the Ordnance Survey National Grid (EPSG:27700) and ETRS89 (EPSG:4258).
Impact
The discoveries that prevented the next strike.
51 Uncharted Utilities Found
Exodigo identified 51 utilities that appeared on no existing record.
70 cm Record Discrepancies
Mapped utilities were found as much as 70 centimeters away from recorded positions.
136 Depths Verified
Exodigo verified depth on 136 utility lines, giving crews more confidence before digging.
208 Lines Resolved
The final Composite Utility Map resolved 208 total utility lines to PAS 128 Quality Level B1P.
Trial Holes De-Risked
Colas Rail confirmed planned trial holing and excavation would have clashed with unknown or inaccurately mapped utilities.
Exodigo provided invaluable data that reduced redesign and delays due to uncharted services. We look forward to implementing this technology on future projects.
— Alejandro Moreno, Business Development Director, Urban & New Business, Colas Rail UK
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