Sydney CBD and South East Light Rail (CSELR) - Land Surveys

ClientAccionaLocationAustralia, NSW
ConsultantLand SurveysContractorBryce Hoffman

Project Summary

An exciting construction project for Sydney CBD infrastructure - the CBD and South East Light Rail (CSELR). The 12 kilometre alignment features 19 stops, extending from Circular Quay to Central Station, through Surry Hills to Moore Park then branching off to Kingsford and Randwick. The project included 10 substations, a stabling yard, and a maintenance facility.

The CSELR was designed, constructed, operated, and maintained by a private operating company as part of a Public Private Partnership (PPP). The PPP contract was awarded to the ALTRAC Light Rail Consortium, which included Acciona, Alstom, Transdev, and Capella Capital.

Land Surveys was commissioned by Patriot Environmental Services. Patriot was engaged on the project to provide the non-destructive digging services. This system is used to safely expose the utilities in order to treat them, or relocate them. Patriot engaged the vast skills of Land Surveys for surveying and utility mapping to be undertaken.

Land Surveys was tasked to map all the existing utilities and associated structures through the Surry Hills zone, which is from Central Station, through to South Dowling Street, Surry Hills via Devonshire Street.


The Challenge

There were multiple challenges involved, including the rail being constrained by its horizontal and vertical geometry, as well as being in the middle of Australia’s largest and most densely built up city. This resulted in the need to treat the existing utilities required to protect them from any vibration and active loads from the rail, or completely relocate them outside the construction zone.

The service records showed that some of the services were more than 100 years old. Some records were incomplete, or missing, creating a significant challenge on the project. In addition, more than 1,500 undocumented services were identified across the alignment during the service mapping and investigation work completed by Land Surveys with other service locating companies.

The scale of this project was exceptionally large, and as such, it took a lot of resources and coordination. Consultation was required with each asset owner, as well as an assortment of required permit grants, whilst maintaining utility supplies to schools, businesses, and homes at all times in the area.

The Solution

The first step was to document all the existing services. This was done via locators to mark out the information on the ground, along with undertaking investigative trenching. The data was then captured using 12d Field software. As there was a vast number of services to document , the team used 12d Model map files with 12d Field code lists to allow them to process the data as they picked it up. This allowed them to see any errors or issues immediately. They documented this information with the required GIS database attached to each of the CAD elements as per the AS5488-2013 including additional attributes relevant to the project. They used the attributes to get 12d Model to auto pipe and culvert the services to display their extents, as some services banks were more than 2m wide and more than 1m thick. There were pipes nearly 1,200mm in diameter. This information was critical to understanding the space they were working with, and to ensuring they met the separation distances required by the safety in design specifications.

After collecting the data, it was sent to the client’s design team to design the models. The design team was also using 12d Model to design the utility model placements and civil design. Due to their use of 12d Model, they could provide 12da files that Land Surveys could easily drop straight into their 12d Model project files, and overlay to their survey models. This enabled them to instantly see the relationship between the design and the existing services, in 3D.

They then went on site and marked up those designs using 12d Field. At this point, if any engineers, supervisors or construction crews had any queries around measurements, or separations, the Land Surveys team was able to answer those queries onsite. They were also able to pull sections and add data in as needed, generate reports and distribute important information all from the field. Any new data collected was automatically processed as described above. Once the pickup was done, there was little to no additional processing required, and with 4G data access, they were able to email the collected data fully processed straight to the client and their design team, removing the time loss of having to go back to the office. This whole process saved large amounts of time by increasing the efficiency of the crews in the field, and allowed the engineers to make important decisions in the field much faster and more effectively.

Designs were being developed mainly based on ‘B’ class data with accuracy up to 500mm vertically and horizontally. When the design model was issued, the accuracy of the existing utility model was improved by being upgraded to ‘A’ class through investigation trenching, resulting in some clashes. Clashes had to be detected as soon as possible to allow the designers to rectify significant clashes. Using the clash detection functionality in 12d Model, the Land Surveys team was able to identify any clashes as the existing services model improved. The client was then notified immediately and issue alerts generated. The designers were also notified, enabling them to adjust the design accordingly while still under the review and endorsement process. Most, if not all, of the issues were rectified prior to the main scope of works commencing, reducing the chances of any delays by the work crews (and associated costs).

To ensure safety onsite, the project required an excavation permit to allow the teams to safely excavate. This was achieved by ensuring each excavation was marked up by the utility locating teams, and the crew’s walk-through, in regard to the services they were working around and the restrictions that were in place. The teams used the utility model Land Surveys had generated in 12d Model to ensure all services were located and marked up on the ground, given they could not rely on the DBYD as the DBYD did not include decommissioned services, property connections, or any of the 1,500 undocumented services located. The team was also able to use 12d Model software to extract out attributed data such as the pipe size, the configuration, the material type, and the extent of the banks. Land Surveys, along with the Utility Mapping teams, helped run permit training with competency tests to ensure the crews working around the live services could understand the marking on the ground, in accordance with AS5488, along with the procedures and restrictions required by the asset owners for working around live services.

The Result

By applying these processes and using the intelligent functions of 12d Model in the field, the project was able to bring the service strike rate and near miss incident rate involving utilities down significantly.

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