Power Line Communication Based Real Time Train Tracking System for Addis Ababa Light Rail Transit

In railway traffics the low friction between wheel and rail causes long braking distances, normally much longer than the driver"s sight distance, i.e. if the driver starts the braking when he discovers a problem on the track it is too late to stop the train. The conclusion will be that the railway traffic can not only rely on the driver for the traffic safety, there must also be a signaling or even an automatic surveyor system, which can supervise the positions of different trains along the track and organize the traffic. Having the traffics information on the track helps to avoid situations of conflict and those that might be potentially unsafe. There are different train detection systems in service worldwide. Track circuit, Axle counter and GPS are the most prevailed approaches. The first two types provide the information that whether the section is occupied or not. They don"t provide the information "where exactly the train is?" Beside Axle counter has huge installation cost and maintenance cost. Regarding GPS, since it is using satellites to determine the location of the train and the accuracy is dependent on the no of satellites tracked, the error spread is variable. In addition to this it doesn"t operate in tunnels like we have for A.A LRT (Addis Ababa Light Rail Transit) track, from St. George church to Atikilit tera. Not only these but also since the satellites are administered by third party, the operation is totally out of the control of the railway company. With this research, Power line based real-time train tracking system is proposed for A.A LRT. It has an advantage of providing continuous distance information, low capital cost, low maintenance cost and under a full control of Railway Company. Since it uses the power line communication, the channel is secured since the train is on the track and the overhead contact system exists. Beside of the train detection software is developed to display visually the train movement according to the distance information obtained. The system can also extend to broadcasting the information obtained via a possible communication means (GSM-R) to control center or other trains on the track. This increases the movement confidence of the trains since the driver operates with the knowledge of distance, direction and speed of trains at the back and front that helps a lot for efficient use of the track.