Increase of Efficiency in Wireless Train Control Systems (ETCS Level 2) by the Use of Actual Packet-Oriented Transmission Concepts

The European Rail Transport Management System (ERTMS) was introduced by the European Union (EU) to harmonize the nearly 18 different national train control systems which are currently in use, to accelerate the interoperability of the passenger- and freight-transport and, finally, to increase the utilization of tracks by dynamic train control. The essential components of ERTMS are the train-specific, cellular, professional mobile radio system GSM-R (GSM-Railway) and the so-called European Train Control System (ETCS) which provides, by its second expansion stage (ETCS Level 2), the control- and signalling-information between the train and the related control location via GSM-R in a connection-oriented and wireless way. This wireless and connection-oriented approach will be the bottleneck of the system, which considerably limits the possible number of voice- and data-connections in each cell at the same time and will cause a deadlock of the system, if the number of users will rapidly increase (e.g. accidents, freight depots, lines with a high and dynamic volume of traffic). Within this paper the first part of a packet-switched approach is presented to counteract this expected deadlock by taking into account that the GSM-R infrastructure, which is often already installed by the national railroad operators, also should be used to save the high capital investment of those companies.