Ang1/P138 Technical Aspects of Railway Interoperability
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ASME-GREEK SECTION, First Nat. Conf. On Recent Advances in Mech. Eng., September 17-20, 2001, Patras, Greece Proceedings of 1st Nat. Conf. On Recent Advances in Mech. Eng September 17-20, 2001, Patras, Greece ANG1/P138 TECHNICAL ASPECTS OF RAILWAY INTEROPERABILITY K. Giannakos V. Profillidis General Director of Infrastructure Associate Professor of Greek Railways Democritus Thrace University 1, Karolou St., 104 37 Athens, Greece 1, Vas. Sofias St., 671 00, Xanthi, Greece ABSTRACT The fragmentation of railways by various barriers means that interoperability does not happen ipso facto. Sig- Recent technical advances concerning railway inter- nificant efforts have to be made in order to reduce the regu- operability are surveyed and suggested in this paper. For latory, technical and operational differences that could im- differences in track gauge techniques of variable gauge ax- pede the free train traffic without any stops at borderlines, les, of powered axles with adjustable gauge are analyzed. [2]. Incompatibilities in electric power are overcome through The technical interoperability aspects that shall be ana- techniques such as the multi-system electric locomotives. lysed in the following are: For differences in signalization new techniques are investi- • Track gauge, gated. Advantages from the application of these interopera- • Electrification/Electric power, ble systems are clarified. • Signalling – traffic regulation. KEYWORDS 1. The railway track Railways, Interoperability, Track gauge, Electrification, 1.1. The track gauge Signalization, The track gauge is defined as the distance of the gauge- sides of the rails, measured at a distance 14 mm below the INTRODUCTION rolling surface, [3]. Tracks of various gauge have been built: In Community Directive 96/48, interoperability is de- ♦ Normal gauge, e =1,435m: Most lines have been built fined as the ability of the trans-European high-speed rail with this gauge, which was concluded to optimise rolling system to allow the safe and continuous traffic of high-speed stock dimensions. Regular gauge rails are allowed to have trains, under achievement of specific performances, [1]. maximum deviations of + 10 mm to – 3 mm from a value of This ability is based on a set of regulatory, technical 1,435 m. and operational prerequisites that have to be kept in order to ♦ Metric gauge, e = 1,000 m or e = 1,067 m. Mostly sec- fulfil the basic requirements. Thus, we are referring ondary lines have been built with this gauge. The lines of the respectively to: Peloponnese and of Volos-Paleofarsalos are metric gauge i. Technical Interoperability Data which comprise all con- lines. All other OSE lines are of regular gauge (except the structional data presenting differences that create interopera- rack railway line Diakofto-Kalavryta that has a gauge of bility problems, and 0,75 m). ii. Operational Interoperability Data, which comprise prob- ♦ Broad gauge, e = 1,524 m (Russia), e = 1,672 m (Spain) lems of administrative, organizational or operational nature and elsewhere. Rails of this type were built as a contrast to that create non-compatibility, affecting inter-operability to regular gauge, mainly for political reasons, so that no regular an equally significant degree. gauge railway vehicles could intrude in these lines. The development of a rail network across Europe con- It is evident that gauge differences do not allow a train tinues to be impeded by differences in track gauge, loading- or/and a single vehicle that operates at a given track gauge to gauges, energy systems and more than twenty noncompati- use the tracks in a rail network with a different gauge. ble to each other train traffic control systems. Of utmost importance in the attempt to overcome these problems is the 1.2. The current situation of railways in Europe in re- co-operation between the rail networks. Technical, as well gard to track gauge as commercial interoperability have a long way to go toward Maybe the greatest interoperability barrier for the rail- the completion of a trans-European network, and shall con- ways in Europe today is due to the different track gauge tribute to the higher goal of the European integration. values that exist in the various networks. - 1 - ASME-GREEK SECTION, First Nat. Conf. On Recent Advances in Mech. Eng., September 17-20, 2001, Patras, Greece At the beginning of the railway era, that is, from 1830 The substations can be fed with electrical power, [5]: up to about 1850, the first railways were built in order to ♦ from the national high-voltage power distribution net- meet the transport needs on a regional scale, [4]. work with a frequency of 50 Hz, in Europe (60 Ηz for the It was then impossible to predict the importance and USA). the role that this new means of transport would assume, nor ♦ from a special high-voltage network, the frequency of that the connections between the various lines would lead to which (usually 16 2/3 Ηz) is significantly lower than that of the creation of a transcontinental network. the national network. This special network might be con- As regards the narrow (metric) gauge, it allows for the nected to the national network, but it also can be in- construction of tracks occupying less ground area and the dependent, that is it can have its own power generation units. use of curves with a smaller radius. Thus, metric gauge was The transmission line from the substations to the vehi- used everywhere where a low cost construction was needed, cles usually is of single phase. The transfer of power to the primarily in secondary lines, as well as in mountain regions. electric locomotive can be effected in two ways: Figure 1 depicts the current situation of the various tack • an overhead line, which is used in interurban and (some gauge values in Europe. times) in urban railways and metropolitan railways. Different track gauge values have been also chosen • A third rail, which is used in metropolitan railways and outside Europe. The Indian network has four different track (some times) in urban railways. gauges, two of which (1,676 m and 1,000 m) are dominant. In Australia there are also three different track gauges. In Return of the power is effected through the rails. Either Latin America, Argentina for example, the capital Buenos one or both rails can be used. Aires is the starting point for railway lines with three differ- ent track gauges, [5]. 2.2. Interoperability of electric power systems in Eu- Where there is a transport traffic flow on lines with rope different track gauges, there are problems emerging that Direct current has more advantages than alternating have to be overcome in special stations through operations current in regard to the traction circuit. Thus, for a long time that are more or less time-consuming and costly. (from early 1900’s to 1950) priority was given to better en- gine performance. Since series direct current engines until 2. Electric power recently provided the best conditions for the movement of 2.1. Electric power sub-systems vehicles, an electric power system that was using direct cur- The two electric power sub-systems, that is, the power- rent was sought. supply circuit and the traction circuit have different de- Voltages that were mainly used, were: mands, and depending on the priority that is given to energy − 750 V, mainly for electric power by a third rail, transfer (power-supply circuit) or to energy use (traction − 1,500 V, which was used more than the others, circuit), different electric power systems have been devel- − 3,000 V. oped. These voltages are very low compared to the voltage The power-supply circuit comprises, [3]: used for transmission (in Greece 150.000 V, 220.000 V). − Substations, Thus, electric power with direct current results in substantial − Transmission lines, cross section sizes of the power transmission line (400÷900 mm2) and placement of the substations at very small dis- tances to each other. Substation distances are 15÷20 km in 1.000mm 1.435mm the case of a 1.500 V voltage and 35÷40 km in the case of a 3.000 V voltage. 1.524mm Electrification power with alternating 15.000 V, 16 2/3 1.600mm Hz current is applied in Central Europe (Germany, Austria, 1.668mm Switzerland) where the substations are fed by special low- voltage power generating units and in Northern Europe Various gauge (Sweden, Norway), where the substations are fed by the na- tional network with a frequency of 50 Hz. This electric pow- er system represents 20% of electrificated lines worldwide, [5]. In Figure 2 the existing electrification systems in Eu- rope are presented. It is obvious that for each system differ- ent electric locomotives are needed, resulting in the need to change the traction unit at the respective country’s border. Consequently, it has emerged the need for production of bicurrent and of multicurrent (multi-voltage) traction units in general, which can be operated with more than one electric power systems. Figure 1. The various values of track gauge in Europe. - 2 - ASME-GREEK SECTION, First Nat. Conf. On Recent Advances in Mech. Eng., September 17-20, 2001, Patras, Greece 3.000V to enter specific section of a line, only when it has been as- certained that the line will remain free. 1.500V − protection from another train that moves on another line, 25kV, 50Hz which however intersects or merges (by means of a track 750V, 3rd rail transition) with the specific line. 15kV, 16 2/3 Hz 3.2. The interoperability of the European network in regard to signalling and traffic regulation In Figure 3 the existing in Europe signalling systems are given. There are 16 types of system throughout the entire European continent.