An overview on urban rail transport technologies

Road transport is one of the main sources of air pollutants emissions in urban areas, especially nitrogen dioxide, particulate matter, volatile organic compounds and benzene. Air pollution directly causes serious and chronic diseases such as asthma, cardiovascular problems and lung cancer. The energy transition and the new regulations introduced in recent years, envisage the elimination of all forms of fossil fuel by 2050. As a consequence, electric transport is one prosecutable solution to concretely face the mobility issues. At present, there are several types of urban electric transport systems, differentiated by size, capacity, realization costs and end use [1]. This article aims to describe in detail the state of the art and the technology currently used in the main urban rail transport systems. In addition to the main features, the analysis will also include the different forms of power supply that characterize the transport means, the different protection systems and finally, the overall costs