## 7 Conclusions and Summary of the Key Findings  
Ultimately, many scholars believe that HSR services may benefit the society, and several nations are considering building HSR networks. However, while HSR services undoubtedly generate significant socio-economic benefits, their effect may be exaggerated, not necessarily benefiting the whole population. Furthermore, this research has identified a knowledge gap in that there has been no previous evidence for the measurement of HSR's impacts on the young and older generations. Therefore, unparalleled big data sets have been adopted to determine the socio-economic effects through novel Python models. The outcomes point towards young and older generations to gain lower benefits derived from HSR networks in some countries. This research highly recommends that HSR authorities and policymakers pay more attention to local HSR services on both groups, especially the PD2 and PD3 factors. It can reflect the life quality of the entire society, same as economic benefits. Moreover, the impacts of HSR on the country's economy has been reflected through the labour markets. This study highly recommends concern in the rate of employment (ED2 and ED3) after operating the HSR services in the area, as it reflects capabilities of overall country's economy. The case study of five HSR networks' socio-economic effects has been analysed by using long-term data sets. Moreover, the KNN and PCC models have been applied using novel models to assess the sizes of social impacts. The benchmarking study results indicate that SNCF's and Rerfe's networks have the highest advantages for all demographics. Those networks are followed by CR, Korail, and JR Central, where their social benefit schemes do well for the non-adult population and provide them with enough benefits, especially in terms of education as ED1, ED2, and ED3. This study is the world's first analysis of the educational usefulness of the HSR. The outcomes of this research are expected to provoke full benefit for all, leading to long-term improvement. The expert opinion and feedbacks have been assembled from 30 railway experts globally to adapt our findings for a practical recommendation. The analysis for all networks except the Japanese network is higher than the 'agreed' level. In addition, these experts also prioritise policies and projects to increase the effectiveness of HSR networks as follows: providing access to important cities, connecting to various modes of public transportation or transportation hubs, and offering reduced or special tickets. By supporting a globally sustainable development policy, this study has aimed to assess and increase the socio-economic benefits from HSR services for both existing and upcoming networks. These policies point towards the advantages and practicability of improving socio-economic benefits for each society. Conceptualisation, P.R. and S.K. ; methodology, P.R. ; coding, P.R. ; validation, P.R. and S.K. ; formal analysis, P.R. ; investigation, P.R. and S.K. ; resources, S.K. ; writing--original draft preparation, P.R. ; writing--review and editing, P.R. and S.K. ; visualisation, P.R. ; supervision, S.K. and Z.-J.S. ; project administration, S.K. ; funding acquisition, S.K. All authors have read and agreed to the published version of the manuscript. This research was funded by European Commission, grant number 691136; and Japan Society for the Promotion of Sciences, grant number JSPS-L15701. The APC was funded by MDPI Invited Paper Program. Not applicable. Informed Consent Statement: Informed consent was obtained from all subjects involved in the study. Data Availability Statement: Publicly available datasets were analysed in this study. This data can be found here: [[https://data.worldbank.org](https://data.worldbank.org)]([https://data.worldbank.org](https://data.worldbank.org)) (accessed on 5 November 2021). The HSR experts' feedbacks are not publicly available due to the GDPR rules.