Monitoring reduces exposure, strengthens oversight on HS2

HS2 is one of the largest, most ambitious infrastructure programmes underway in Britain. Main Works Civils Contractor, EKFB (Eiffage, Kier, Ferrovial Construction and BAM Nuttall joint venture) is delivering 80 kilometres of the new high-speed railway. Its scope comprises of 81 bridges, and seven kilometres of green tunnels, delivered by a workforce of around 7,000 people.

Near the small village of Calvert, in Buckinghamshire, one section of the project stretches for ten kilometres. Within a corridor as narrow as 50 metres, teams are building four rail tracks alongside haul roads, cranes, and constantly moving heavy machinery. At peak activity, as many as 200 people may be working within the same area. It is a tightly coordinated environment where multiple structures progress in parallel, and where the physical landscape can change from week to week. This makes maintaining consistent surveying lines of sight to important targets challenging.

Keeping Calvert on track – the surveyor’s role

The challenge is not only to deliver ten kilometres of infrastructure in the right place, to the right dimensions. It’s also tracking how structures and surroundings behave as construction moves forward.

Emanuela Chimiuc, Survey Manager at EKFB, manages the Calvert Area – she and her team are responsible for surveying and monitoring activities. They establish survey control and record as-built data to ensure that the completed construction matches the design. Additionally, they monitor movement at critical locations across the site to ensure that the deformation of structures and any adjacent assets are within the tolerances of design expectations.

“We rely on accurate survey data to confirm whether assets behave within design limits,” Chimiuc explains. “This allows us to identify trends early and provides reassurance that works are progressing safely.”

Safety leads – productivity and accuracy keep pace

Providing accurate data in such a fast-changing environment is not straightforward. Survey control must remain stable as works progress, digital models must reflect the physical site, and even small movements must be understood in context. There is little margin for error.

Gathering that reassurance, however, has traditionally required people on the ground. Monitoring has often meant sending surveyors into active work zones to take measurements in person. However, in the HS2’s continuously evolving construction environment, changing area accessibility and site activity can make manual surveys difficult, impractical or unsafe. On a corridor carrying heavy machinery and constant movement, more time on site means greater exposure to risk – and, at times, slowing construction to collect the data.

At EKFB, the expectation is that everyone goes home safe every day, and this culture shapes how such risks are managed. Rather than accept any potential trade-off between safety, accuracy, and productivity, the team looked for ways to reduce the need for physical presence in the first place.

In dynamic construction sites with unpredictable hazards like changeable weather, access restrictions, and moving machinery, that means careful coordination, collaboration, and reliable data. “Every step we take at work is with safety in mind,” says Emanuela Chimiuc.

Fewer boots on the ground, more eyes on the data

Looking for a way to retain the same level of accuracy and precision while reducing reliance on physical presence, the team decided to integrate an automated monitoring system.

Their solution included installing six Leica TM60 monitoring total stations on fixed, secure platforms across the site. The instruments automatically measure a network of prisms mounted on key structural elements, enabling continuous displacement tracking. Four GNSS receivers - configured as two baselines – provide independent geospatial reference and crossvalidate the total station data. The total stations’ integrated cameras allow the team to verify line-of-sight conditions and investigate issues remotely, and record images for progress records, reducing the need for physical checks in active work zones.

The instruments feed data directly into Leica GeoMoS platform, where it is processed, analysed, visualised, and stored within a single system. Because the solution is always on, measurements are captured continuously rather than at large intervals. Chimiuc’s team could predefine thresholds to trigger alerts automatically when movements approach or exceed expected limits. Engineers can access the information remotely, review trends, and respond without needing to stand beside the equipment. Overall, a smarter, safer, more efficient solution.

For Emanuela, the impact was immediate. “It made things simpler straight away,” she says. “The main principle was to reduce the amount of boots on the ground for safety and efficiency, and choose a technology that would keep the operational costs under control in the long run.”

Simpler. Faster. Safer. Clearer.

The benefits extend beyond data capture. For Joelene Godwin, Instrumentation and Monitoring Engineer for the Calvert Area, the automated workflow provides clearer visibility of structural behaviour across the site.

“The survey team feeds the monitoring data onto my dashboard. This has helped me provide accurate data analysis and make the right decisions at my contract technical committee meetings,” she explains. With displacement trends available in near real time, the team can compare results against trigger levels and implement predefined action plans when required.

“Technology and digitalisation have helped reduce human exposure, speed up data collection, and keep everyone informed in real time,” says Chimiuc. “This way, we keep safety the absolute priority and still meet construction deadlines.”

The automated monitoring system reduces unnecessary surveyor visits to hazardous areas while strengthening the team’s overview of structural behaviour. Comprehensive, continuous measurement data available to stakeholders across the Calvert Area has effectively reduced risks and heightened responsiveness, solving a pressing construction challenge with a pragmatic technical solution.