Modern Railways: Communications Systems and Technologies

The articles in this special section focus on the connection between railways and wireless communications and contains many interesting contributions to the most relevant research topics in this field. Besides the “connected car,” the “connected train” is one of the most relevant use cases for modern communications systems and technologies posing unique challenges. High data rates to communicate with trains running at 300 km/h, Internet access to massive transit systems with up to 1000 people in 100 m long metro trains, ultra-dense sensor networks to know the condition of all the subsystems within the train, and vehicle-to-vehicle mission-critical services to move trains safely and reliably imply many challenges in the communications field that could be solved with novel wireless communication technologies.