Is GSM-R the limiting factor for the ERTMS system capacity?

Abstract: The European Rail Traffic Management System, ERTMS, is introduced as a common signalling system for the European railway network. ERTMS consist of two main parts, the signalling part ETCS and the radio transmission system GSM-R, based on the well-established GSM standard. The question to be answered in this thesis is if the capacity of GSM-R is limiting the ETCS part in any way. If that is the fact, how can the limitations be overcome? Looking forward, will public mobile system with high transmission capacity like GPRS, LTE etc influence GSM-R? GSM-R year 2020: how will it look? The thesis describes the basic functions of ETCS and GSM-R, and the way they are interconnected. The study shows that the capacity of GSM-R is sufficient for signalling on the line, even for high speed traffic. Problems occur with a high density of GSM-R users in a limited area, for example at large stations and marshalling yards. Also the combination of a station, with many but slowly moving units, and a main line, with few but fast moving units, passing through the same area can cause problems. The thesis describes various ways to solve this issue. Right now these problems are solved with advanced cell-planning and the use of lower level implementation of ERTMS, not depend on GSM-R. In the longer run the main solution is to introduce higher capacity packet-switched solutions like GPRS. An even greater problem at the moment is that public mobile operators providing high-speed data services in the near-by frequency bands interfere with GSM-R. The solution to this problem is presented as well as the problems the solution itself is causing. In the long term perspective ERTMS will depend more and more on reliable data communication by radio and packet-switched high speed radio solutions, which will definitely be a part of ERTMS. To address the question raised in the thesis title: is GSM-R the limiting factor for the ERTMS system capacity? NO, considering the actions taken and the sometimes unconventional solutions used based on engineering expertise and creativity, GSM-R is not the limiting factor in ERTMS right now. YES, in the long run and with broader usage of ERTMS, GSM-R has to have a higher capacity, more functionality and be a more standardized system: more “plug&play” than “plug&pray”.