## 6 Conclusions  
The aim of our research project was to design and to validate a railway safety system for an isolated environment and especially for Nordic trains in Quebec based on IEEE 802.15.4 protocol. This new low-power rail security system has been validated on the rail tracks of northern Quebec, and the results obtained define a mean range of 3 km and a maximum range of 10 km. The railway company Tshiuetin has approved the results of the tests. It is certain that a greater range between the locomotive and the Hi-Rail pickup could be obtained with the same power by placing the antennas at higher heights. However, the locomotive crosses tunnels, which makes this eventuality impossible. It is also necessary to imagine that the winter conditions are very hard with snow accumulation and ice on the locomotives. Therefore, it is required to have a compact and aerodynamic antenna: it will be necessary to test the system again during the winter and the very hard climate conditions of the northern Quebec. The methodology we used for our tests could have been improved if we had had full control over the movement of the locomotive, as it has been the case with the Hi-Rail pickup we used. Nevertheless, the company could not monopolize a convoy for us during our tests, as the mines continue to produce iron ore that fills the rail cars to be driven to the port without any delay. Therefore, we had to adapt our methodology to the situation: despite everything, this choice of methodology allowed us to test deeply our telecommunication system.  
The next step requested by the Tshiuetin company confirms the success of this first project: the company wants to make the system bidirectional so that the driver of the locomotive is warned of the presence of employees on the railway in this isolated environment where there is no internet connection and no electricity network. Another avenue for the  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Results**} & **Modelizations and** & **On Site (Railway** & **Wishes of the** \\  & **Simulations** & **Track)** & **Railway Company** \\ \hline Mean Range & 3.5 km & 3 km & 2 km \\ \hline Maximum Range & 15.36 km & 10 km & 3 km \\ \hline \hline \end{tabular}
\end{table}
Table 2: Summary of results planned (before tests) and obtained (after tests).  
development of an ultra-modern solution in this isolated environment would consist of mapping the GPS coordinates of the Hi-Rail pickup transmitted by the XBee system on an offline tablet located in the locomotive. Thus, the driver of the locomotive could see in real time the position of the employees on the track.  
After developing this geolocation system with an offline tablet, another paper will be written and submitted to Sensors. Finally, the prospects for improving the safety for the company based on this project are significant, especially in this isolated environment. Our system gives a very important first layer for a railway safety system with the possibility of implementing lots of other functionalities. Every difficult step of designing the system has been achieved with a scientifical process: this gives lots of complete and precious details to take into account for any scientists who want to develop a telecommunication system in those specific places that are isolated environments on the earth.  
Note also that some important railways companies that drive iron from north Quebec follow with lots of interest the evolution of our railway security system to implement in the near future on their tracks.  
Conceptualization, L.F., H.I. and M.I.; methodology, L.F. and H.I.; software L.F.; validation, L.F. and A.I.; investigation, L.F.; data curation, A.I.; writing--original draft preparation, L.F.; writing--review and editing, M.I.; visualization, A.I.; supervision, H.I. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
Generated during the study.  
The authors declare no conflict of interest.