6. Conclusion
Received results prove extraordinary possibilities in regards to the laser scanning technology. Combination of the
scanning together with total station and GNNS satellite surveying allows for point cloud orientation in any common
coordinate system. Presented technology can be adopted to all disciplines where a millimeter accuracy is required.
Point cloud provides information for spatial objects visualization. Based on that it is possible to run an inspection,
measurements and analyzes directly in 3D environment. Laser scanning technique is especially valuable in industrial
facilities and communication routes surveying. As a standard this technique is being used in detailed analyze of
structure gauge. It is also definitely possible to use it in a tram tracks and surrounding infrastructure measurements
especially if the tracks are located inside of the tunnel as in presented example. High accuracy and redundancy
allows for identification and gathering points which represents each splint. Precise information about tram track
position are the base for various analyzes and development in surveying services and diagnostic studies. In tram
track measurements it is vital to properly configure and plan laser scanning measurements. It is related to the
importance of proper spatial positioning of the tram track which is partly located below the level of the tunnel sill.
Influence on the resulted point cloud has following factors: setting proper point cloud resolution, localization of the
stations and distance between each one of them. Objective verification of the laser scanning data accuracy and
quality needs to be verified against the reference measures done with classical equipment dedicated to the particular
task. With some modification of the driving elements and items applied directly to the tram track it is possible to use
trolleys and measuring systems from the train track metrology.
Results based on the point cloud are good but time demanding. Unfortunately it is related to the analyze
workflow which is currently manual or semi-automatic. Improvement on the workflow algorithms and adaptation of
proper software might allow to improve the process.
During site measurement innovative solutions in regards to the tram track maintenance were used. Special
surveying control network was established in the field. There are many similarities within its functionality to the
railway geodetic network. Such network can be used in challenging track sections, like: fast tram tracks and tram
tracks in tunnels. Fixed points positions are basing on metal plates mounted to the side wall of the tunnel or traction
poles. Magnetic reflectors or scanning targets applied to the reference points are being used in the laser scanning.
Those points might be used as a reference for any kind of surveying measurement and diagnostics taken in the tram
track and tunnel area. Grid points’ specification and coordinates’ high accuracy can secure any kind of execution or
surveying tasks related to rail transportation.
Important limitation during the work with point cloud is the big size of the data. It requires high capacity hard
drives and extremely efficient computers for a comfortable and fast data processing. Mentioned challenges are being
partly solved by development of the computer and software technology. Computing power of the hardware and
software abilities is growing rapidly. Further, more and more solutions is being transferred to a virtual services. This
brings a possibility to exchange the data with anyone who needs to get access to use and take the best from it.