Broadband Wireless Communications for Operational Needs
Broadband wireless communications needs for railway applications are quite growing since several years, as presented in Chap. 1. Services to passengers are very demanding in terms of throughputs, as presented above. Other applications requiring broadband wireless communications are presented in this section. Among these applications, we studied maintenance activities, video surveillance applications and other applications, such as smart metering and freight. We decided to separate the maintenance and the video surveillance applications even if they are strongly related. On one hand, maintenance can be performed by using video techniques, but also other techniques, such as WSNs. On the other hand, the video surveillance can be used for maintenance purposes but also for other applications, such as security.
With the rapid innovations in computer science, an increase of amount of data, coming from many sources is observed in many domains, such as railway domain . The traditional data-collecting methods rely on selected measurements over specific assets. Henceforth, it is now possible to perform continuous collection of information from several sources from the entire railway system. This phenomenon leads to an improvement of monitoring and maintaining of railway system by using real-time information.
Maintenance operations lead to accumulative delays, that can disturb railway traffic. Scheduling maintenance work is quite difficult due to the high occupancy. There is then a high demand for efficient and reliable maintenance operations based on frequent measurements of the different parts of the railway system. Thus, continuous data processing and high quality decision making are required. Video is one of the technology that can be used to monitor the systems leading to high required throughputs to transmit the data.
ERRAC targeted for the year 2020 to double passenger and freight traffic by rail. Taking into account this expected growth in passenger and freight volumes and the aging of existing infrastructure, maintenance needs and costs are likely to increase significantly in the coming years. It represents then a major objective to reduce the life-cycle cost of the railway transport. One way to reduce the cost of rail services is to limit expenditures linked to the operation of services, including energy consumption and maintenance.
Maintenance of rail network infrastructure has to be safe, reliable, cost-effective and sustainable. A significant part of the costs for reliable high capacity infrastructures is related to intensive maintenance, most of which is preventive. Thus, maintenance costs have to be reduced by especially simplifying procedures and automation. Better maintenance strategies can be based on risk-based or condition-based analytics, using more reliable sensor technology to detect real asset condition. Furthermore, enhanced maintenance procedures can be based on remote infrastructure condition monitoring and automated, self-inspecting, adjusting and correcting devices. The maintenance systems can be built on cutting edge measurement and monitoring tools that provide static and dynamic data from all relevant components of the rail infrastructure, using train-borne, wayside and remote sensing measurement and monitoring systems. Automation should be achieved for routine maintenance checks, as well as for repetitive tasks, such as track relaying, ballast renewal, tamping and alignment.
The amount of data that has to be raised from train to ground are then more and more important and requires high capacity wireless communications between train and wayside. An alternative could be that some pre-analysis on board the train is performed to reduce train-to-ground transfer. All the systems are presented in this section.