Suspended monorail system dynamics: fundamental and practice

Abstract

Urban transportation systems are facing severe challenges due to the rapid growth of the urban population, especially in China. Suspended monorail system (SMS), as a sky rail transportation form, can effectively alleviate urban traffic congestion due to its independent right-of-way and minimal ground footprint. However, the SMS possesses a special traveling system with unique vehicle structure and bridge configuration, which results in significant differences in both the mechanisms and dynamics problems associated with train–bridge interaction (TBI) when contrasted with those of traditional railway systems. Therefore, a thorough understanding of the SMS dynamics is essential for ensuring the operational safety of the system. This article presents a state-of-the-art review of the TBI modeling methodologies, critical dynamic features, field tests, and practice of the SMS in China. Firstly, the development history, technical features, and potential dynamics problems of the SMS are briefly described, followed by the mechanical characteristics and mechanisms of the train–bridge interactive systems. Then, the modeling methodology of the fundamental elements in the suspended monorail TBI is systematically reviewed, including the suspended train subsystem, bridge subsystem, train–bridge interaction relationships, system excitations, and solution method. Further, the typical dynamic features of the TBI under various operational scenarios are elaborated, including different train speeds, a variety of line sections, and a natural wind environment. Finally, the first new energy-based SMS test line in the world is systematically introduced, including the composition and functionality of the system, the details of the conducted field tests, and the measured results of the typical dynamic responses. At the end of the paper, both the guidance on further improvement of the SMS and future research topics are proposed.