For public transport companies, it is important that their transport services are not only attractive in terms of price, but also available at the right places (stops, stations) and to the right extent (frequency, transport capacities). Or in other words: that the money they invest provides the maximum benefit for their customers and thus leads to a high attractiveness of public transport and a corresponding use of their services. This applies both to regular operations and to phases with construction or maintenance work.The region of Västra Götaland in south-west Sweden has six important regional centres, which are of great importance in terms of jobs, education, and supply, among other things. For the total of almost 8800 stations (stops, stations) in this area, the aim was to determine how good the accessibility of the regional centres is per station for the years 2018, 2019 and 2020. To allow for making the methods and results generally accessible later, freely available data and software tools should be used as far as possible. Within the framework of this project, methods and measures were first developed together with the client (Västra Götalandsregionen), with which the local accessibility can be determined in a meaningful way. The necessary basic data include, among other things, the locations of all stations and regional centres, the daily number of unique connections from all stations to the centres (in both directions) with the corresponding travel times, as well as the population figures of the spatial units of the region.From the subsequent calculations, a meaningful picture emerged regarding the accessibility of the stations. By comparing the results for the three years it became clear that changes in services, which became necessary due to expansion and maintenance work, sometimes led to major local changes in accessibility. These findings are important, among other things, to be able to estimate the effects on the population at an early stage for the large number of future construction projects of different sizes. On this basis, the timing and coordination of the individual projects can be optimised in order to provide the most attractive service possible during these phases.The project was processed with the open-source tools RStudio (IDE for the programming language R) and QGIS (GIS tool), whereby both the code and the geo-analyses can be used and further developed directly by specialists of the client.