CBTC is Communication-Based Train Control system which is a cost-effective solution for signalling and traffic control of metro and monorail. For the CBTC system that can enhance transportation capacity by moving block control method with less trackside equipment, the radio transmission system is one of the most significant subsystems. Especially, the design and location of all radio-electrical elements is the key factor for the system reliability and availability. Therefore RAPS (Radio Propagation Simulator for CBTC Systems) has been developed together with CITEF (Railway Technology Research Centre of the Universidad Politécnica de Madrid), for the purpose of calculating the radio-electrical signal coverage and power along the track, and arranging a proper layout plan of trackside base stations and associated antennas for each project, in consideration of various aspects, such as tunnel geometry, track configuration, environment affecting obstacles.The simulator considers all the characteristics of the trackside, like tunnel detailed geometry, open areas cartography and computes propagation according to the specific radio parameters. RAPS is provided with a complete set of design tools, radio-electrical algorithms such as modal propagation for tunnels and Okumura-Hata and Ray-tracing for open areas providing a high accuracy in the prediction of the signal strength along the track. Also user-friendly graphical Computers in Railways XIII 111
In high-density railroad sections such as metropolitan commuter lines, there is a great demand for increasing train density in order to relieve traffic congestion. However, it becomes more difficult to shorten train headway, which is dependent on the performance of the signaling system and the rolling stock, as the track form, train type, and train performance become more diverse. Therefore, making diagrams needs the expertise of skilled specialists, for train scheduling, operation adjustment, and equipment design.In order to raise the train density to a maximum, this paper aims to calculate the restrictions in the train intervals that exist between all trains within a certain accuracy and derive a train diagram. We propose the "maximum-density diagram" to refer to a diagram whose periodic time is shortest, on the assumption that the actions of the operated trains in one period are fixed. In practice, we obtain the effective results for railroad operation practices, when we derive the "maximum-density diagrams" of model cases.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.