## 1 Introduction  
Northern Quebec relies on its abundant natural resources, notably its energy, mineral and iron resources, and forestry. The region's economic life revolves around exploiting these resources and is heavily reliant on rail transportation.  
Of all the railway networks in the world, Canada has the third largest and transports the fourth most significant volume of goods. Every year, Canadian railways move 70% of the country's surface goods (including 40% of its exports) and carry 70 million people, meeting motorists and pedestrians at thousands of public and private crossings [1]. In 2019, 1246 rail accidents were reported to the Transportation Safety Board (TSB), which was up from 1169 in 2018. It represents a 17% increase from the previous 10-year (2009-2018) average of 1064 (Figure 1) [1].  
The number of deaths due to railway accidents has also increased by 25% between 2018 and 2019 [2]. One of the most famous rail disasters in Canada was the Lac-Megantic accident in 2013 in which 47 people died [3]. In northern Quebec, railway convoys can contain 200 wagons full of iron ore: therefore, the convoys' length is very important, and it takes about 2 km to stop the train. The most common railway accidents in those sectors are due to rockfall on the tracks or the railway tracks structure defaults because of the very hard winter conditions. The proof: the derailment of the QNS & L train on 6 November 2014, following a landslide that the driver saw too late. The train descended a slope to dive into the Moisie River (northeast of Sept-Iles, QC, Canada), causing the driver's death (Figure 2).  
Within this context [4], Transport Canada defined objectives to improve rail safety, increase safety at grade crossings and along rail lines, and increase public confidence in Canada's rail transportation system. As a solution to this problem, our article's objective is to present with a scientifical process the development and the validation of a railway safety system for isolated environment and based on radio waves using ZigBee telecommunication protocol. Our contribution and the beauty of our paper is to associate known concepts that have never been associated such as ZigBee technology and Nordic freight trains in an isolated environment where internet of things, LTE, and more generally, technologies usually used in cities do not have a place right now. The system was implemented on a train linking two cities on the north coast of Quebec in an isolated environment to assess its performance and demonstrate its viability.  
The paper is structured as follows: Section 2 presents the isolated environment as the important context of the developed solution. Section 3 presents the technological choices  
Figure 1: Number of rail accidents in Canada, 2009 to 2019 [1].  
Figure 2: The derailment of the train in the Moisie river.  
for the radio protocol, while Section 4 presents the mathematical models and simulation with MATLAB and Radio Mobile software. Section 5 presents the case study: it describes the design decisions, the system integration embedded on board as well as the connected watch design and finally, the tests process and the results obtained. Finally, Section 6 concludes the paper with future prospects of study in this area.