Analysis of reliability and capacity requirements expected from a modern rail circulation control system

Initially the paper analyses preliminarily the various hypotheses of system architecture for a modern rail circulation control system. The research focuses on two system-architectures. The first, 'all radio', based on radio communications: both for the link between train and control centre and for the connections between the various entities of the telecommunication network. The other, named 'Opto-hertzian', is composed of a main ground network in fibre optics from which are drawn, when necessary, information later transferred on board train by radio. To compare the two systems, initially the necessary bandwidth was estimated, evaluating the specific requirements of the railway sector. Three different transmission protocol typologies were assumed. Evaluations have been made on a number of trains, checked simultaneously from a generic Traffic Control Centre. The final output of the analysis is an abacus in which, once the amplitude of the Control Centre jurisdiction is fixed, the number of trains to serve can be drawn and, choosing the kind of applications that the system should be provided, it is then possible to obtain the requested bandwidth. Then a reliability comparative analysis was performed. Once the most proper reference parameters for the purpose were identified and considering the bandwidth values estimated, numerical simulations were executed to appraise the performances offered by the two compared systems.