## 1 Introduction
The Railway Administration also wants to provide guaranteed data for the design of new railway constructions or for their reconstruction to designers and also to the public administration through the transfer of selected data to the DTM. The aim of the case study was to assess the effectiveness of remodelling the existing as-built documentation of the railway construction into a common BIM data environment (CDE) and alternatively into a GIS environment, in which the further subsequent agenda of the construction should be kept for the remaining period of its life cycle. Another objective was to identify, through a case study, the existing problems of this remodelling and to propose innovations to the existing engineering procedures and internal regulations that would lead to meeting the above requirements of the Railway Administration of the Czech Republic. BIM models of buildings must be usable for updating the digital technical map (DTM) containing elements of the planimetry (buildings, traffic roads, technical infrastructure networks) and hypsography. DTM is produced by local authorities and transport and technical infrastructure managers for their own use. DTM is unique in their parameters,especially in their content and accuracy. The accuracy of the position and height data of the sub-elements of the DTM contents is characterized by the standard coordinate deviation \(\sigma_{xy}\) and the standard height deviation \(\sigma_{H}\). The accuracy data is given for the element or for the individual points of the spatial determination in the form of the accuracy class specified in the Czech legislative regulation designated as Decree No. 393/2020 Coll. on DTMs. The accuracy is based on the Czech technical standard CSN 01 3410. In addition to the key data, DTM also consists of the relevant information and communication technologies, i.e., hardware and software. In addition to those who acquire it, DTM serves citizens and public administrations as well as private companies, in particular owners and operators of technical infrastructure, planners, investors, banks and insurance companies. The DTM contributes to a better awareness of the land, and the fact that there is no potential problem hidden beneath its surface helps with pre-project preparation, allowing for communication with the relevant authorities digitally. For mayors of municipalities or city districts, up-to-date data maintained in the DTM helps to efficiently resolve operational situations, prevent neighbor disputes, as well as ensure safety and protect the lives of citizens. For example, emergency situations on underground technical infrastructure facilities can be eliminated in a much shorter time using the DTM by not wasting time searching for the necessary documents to eliminate the relevant malfunctions. The DTM allows to work with uniformly processed data on all types of transport and technical infrastructure, to digitalize the processes of construction management, to simplify and streamline the preparation and permitting of buildings, to streamline the planning of buildings and investments and also to minimize the administrative burden, to keep better passports of municipal property, to organize unsettled property relations by comparison with the cadastral map, to streamline a number of public administration activities, to manage the administration of the built-up area in a modern way and to solve a large number of life situations of citizens.