Laser Positional Video Survey for Crossrail West
London, United Kingdom
Project
In preparation for Network Rail’s infrastructure improvements to the Crossrail route between Paddington and Reading, Track Access Services Limited conducted a GBP 40,000 survey along 60 kilometers of the double-track railway using terrestrial laser scanning. A geo-located 3D point cloud and synchronized HD video were produced to define track and line-side infrastructure. The data provided site awareness and support design, as-built verification, clash avoidance, and signal sighting for the Crossrail project.
Solution
Safety issues and avoidance of service disruption were of paramount importance while meeting an accelerated delivery schedule. The selected survey method delivered 150,000 measurement points per second, enabling highly accurate, dense coverage without compromising safety or operations. ProjectWise and MicroStation were used for project collaboration and data post-processing, respectively. MicroStation’s ability to model vast amounts of disparate data was essential to meeting project requirements.
Image: Courtesy of Track Access Services Limited
Outcome
The survey delivered a valuable data set consisting of a 3D point cloud, selected 3D feature strings, selected tagged assets, and an HD video of existing infrastructure. The survey method costs were approximately 75 percent less than the alternative and, in conjunction with Bentley software’s data processing, saved an estimated GBP 228,000. Additional savings resulted from not interfering with train operations. The return on investment will multiply when the survey data is used throughout the Crossrail project.
Software
The capture of survey data and subsequent format conversions facilitated information sharing among all authorized project stakeholders. MicroStation provided the ability to overlay or reference large amounts of disparate data from multiple sources. ProjectWise allowed survey data management, storage, and distribution. Within the ProjectWise environment, Bentley’s BIM technology not only enabled project collaboration but also longer-term asset lifecycle information management.
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Facts
- Using the TAS method, the survey was completed in a single two-hour run of the survey locomotive, compared to the weeks-long process required for a track-side survey.
- At least three update surveys will be required at key project stages, further extending the cost and time savings for data acquisition.
- The data will be used to support future maintenance and operation processes, thereby enhancing the efficiency and cost effectiveness of the survey method.
“Major infrastructure programs need a quick and affordable (and safe) method of surveying the ‘as is’ on the ground, especially after a major commissioning. This survey met this criteria and provided rapid information to our designers to progress with the latest ‘as is’ information possible.”
Rob Farrell
Engineering Data Manager
Crossrail ONW (On Network Works)
