## 5 Conclusions  
This paper presents a detailed overview of the most modern technologies proven through research projects for the future development of smarter, safer, and greener rail transport systems. Firstly, this paper focused on emerging propulsion technologies that are crucial for sustainable transportation, such as those based on battery energy storage technologies, hydrogen fuel cells, and alternative fuels. The literature review showed that battery-assisted propulsion, either through the hybridisation of diesel-electric locomotives or in combination with conventional diesel-electric propulsion, can result in notable fuel savings and greenhouse gas emission reductions, and it can apparently achieve profitability using state-of-the-art lithium batteries. Hydrogen fuel cells have become attractive alternatives to conventional propulsion, especially for smaller-scale railway vehicles. However, hydrogen's increased penetration is predicated by the deployment of novel hydrogen refuelling infrastructure, which, according to the literature, may become profitable in railway applications through achieving an economy of scale. In that respect, the utilisation of optimisation tools to plan hydrogen-based railway train refilling and using on-site hydrogen production facilities to supply heavy-haul freight trains may also play an important role in the future uptake of hydrogen-based railway propulsion systems. Synthetic fuels and biofuels may also be considered as low-carbon-footprint alternatives for railway transportation, but their penetrations are much less certain due to the low efficiency of the synthesis process in the former case and the effect on arable land use and food production in the latter case. Railway transport energy efficiency measure improvements are likely to encompass all of the above alternative propulsion systems and energy sources in the near future, with the end result currently being uncertain due to many technologies currently being researched, developed, and increasingly deployed and investigated in realistic operating conditions. The process of selecting optimal propulsion systems for railway traction roles will likely take years before the field tests ultimately point to solutions that are the most competitive in terms of investment and running costs while simultaneously satisfying the ever more stringent environmental regulations. Secondly, this paper presented the emerging information and telecommunications systems based on long-term evolution and fifth generation new radio (5G NR) networks, with an emphasis on communication systems that are suitable for railway applications. According to the methodology of the integration of experiences from various research projects and different fields, this work presented successful results through achieved specific goals such as energy efficiency or ecological consequences, and it presented broader information so that readers can understand the context and successfully indicate the possible successful compatibility of the researched technology. In this context, the role of Industrial Internet of Things was presented with a particular emphasis on wireless communications and remote sensor networks for railway transportation supervision and management. Special emphasis was also given to narrow-band remote sensor networks for the monitoring of railway infrastructure and atmospheric conditions at the track as key prerequisites for intelligent transport management. Two characteristic cases were presented, wherein remote sensors were successfully used with expert systems and artificial intelligence for railway traffic management, resulting in increased traffic throughput and improved management under adverse weather conditions. It is likely that the new 5G radio network paradigm is going to make notable inroads into railway transportation due to its flexibility, versatility, and support for both narrow-band structured data transfer for smart remote sensor networks and massive broad-band communications, which could support future autonomous railway transport.