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Detailed mapping data is helping new ways of working on a major railway project

Photo: COWI

​In support of the Electrification Programme, a major Danish infrastructure project, COWI's mapping unit has mapped more than 650 kilometres of railway, equalling a third of the Danish railway network. New ways of working and thinking are needed to help getting the most out of detailed mapping data, and that is what they have done in the railway project team at Rail Net Denmark.

​As part of the Danish government's agreement on green infrastructure, all Danish railways are being electrified, securing their independence of fossil fuels.

To support the electrification programme with cost effective data collection, COWI's mapping unit has been asked to deliver highly detailed data sets to be used during several phases of the project.

Pushing technology to the limit

In order to provide Rail Net Denmark with the highly detailed data, COWI has conducted several surveys, including different types of aerial survey methods as well as more traditional land surveying.

The aerial survey for the project was conducted as a combined airplane and helicopter solution, and the data acquisition includes both LiDAR scanning and aerial photos. The final product will include a digital terrain model, 3 cm/pixel orthophotos and topographic maps.

"By using these different techniques, we have challenged the available technology and thereby produced a product of both high detail and high quality," states Rasmus Lindeneg Johansen, Project Manager in COWI's Mapping unit.

Especially the use of the helicopter proved to be a challenge for the COWI team. Flying only 150 metres above the railway and using highly delicate equipment meant that even the smallest irregularities could severely compromise the quality of the products. To ensure that the quality remained intact, COWI's surveyors employed traditional methods to provide specific control points and carried out several control checks during the processing of the data in the production units in India, Poland and Denmark.

By primarily relying on the aerial photos, COWI has been able to deliver the highly detailed products within a tight timeframe and budget.

Saving money and time

Collecting detailed mapping data by aircraft is a cost-saving method compared to traditionally surveying.

"The detailed mapping has an accuracy and richness of details, which is superior to Rail Net Denmark's existing digital maps. Although the new digital mapping does not fully meet the requirements for a land survey of the rail tracks, it is fully satisfactory for the use in the Electrification Programme. Further, it is a factor 10 cheaper than the alternative, the land survey of rail tracks," states Søren Thorpstrup Laursen, Rail Net Denmark's Programme Manager for the Electrification Programme.

The data supports and improves the work of the engineers 

The data produced has already been used by Rail Net Denmark in order to give a more accurate estimate of the scope, detail and cost of the project, and engineers have acknowledged the value of terrain models derived from LiDAR data to support their design works.

"The data produced are made available for the tenderers for the electrification task. They are using the map data for their preparation of their proposals, as a documentation of the status of the existing rail tracks, and as a basis for their design work. Furthermore, the data produced are also used as map basis for the Environmental Impact Assessment for the draft design of changes of overcrossing bridges and the environment impact of the construction work," says Christian Fürstnow, Lead Consultant.

A new an interesting derived use of the map data produced is on another programme of Rail Net Denmark, the Signalling Programme, where the map data will be used for an improved calculation of the gradients of the rail tracks, in order to be able to carry out dynamic calculations of braking distances for the trains.

360° approach creates value for the customer

By combining world-class competencies across the business, COWI deliver a coherent solution to the Rail Net Denmark.

“The project is a great example of how we combine competences in-house and provide our key customer Rail Net Denmark with one company covering multiple skills solution," concludes Kristian Skak-Nielsen.

LAST UPDATED: 16.09.2016