The development of the Budapest-Belgrade high-speed railway has been announced officially in autumn 2016. The railway link has a total length of 350 km, designed for a maximum speed of 200 km per hour. Enhancement of the railway connection is an important condition for achieving better mobility as well as promoting economic development of the regions concerned. There will be obvious changes in the Trans-European network connections and accessibility improvements will be achieved. In the current research the changes of a complex multimodal transport network indicator is assessed. The results indicate the positive changes in the competitive potential of the regions concerned as well as their role in the European co-operation. The other part of the research uses an enhanced accessibility function to characterize and compare multimodal regional and international connections, calculating the changes of the accessibility between some Central-European capitals proving competitiveness of high speed rail compared to other modes.