Proceedings of 7th Transport Research Arena TRA 2018, April 16-19, 2018, Vienna, Austria Infrastructure and operation – research on utilisation of the maximum train speed profile
Andrzej Massel*
aInstytut Kolejnictwa, ul. Chlopickiego 50, 04-275 Warszawa, Poland
Abstract
The aim of the research is to identify factors influencing real utilisation of the maximum line speed. On infrastructure side main factor seems to be differentiation of the maximum speed along the line, which is taken into account with the harmonic weighted mean. As far as rolling stock is concerned main factors are type of train formation (loco-hauled, EMU, DMU), power-to-weight ratio and percentage of powered axles. The extensive database covering the infrastructure data and rolling stock data for intercity train services in various European countries has been prepared. The best utilisation of maximum line speed is in the case of long sections (300 km or more) passed without intermediate stops, at which the influence of acceleration and braking is relatively minor. The utilisation of maximum speed is negatively influenced by significant differentiation of the speed profile (frequent and large changes of speed along the line). The most effective utilisation of line capabilities is in the case of Electric Motor Units (EMUs) with distributed power and high power-to-weight ratio.
Keywords: infrastructure, operation, maximum line speed, commercial speed, speed profile, power output.
* Corresponding author. Tel.: +48-22-4731303; fax:+48-22-6107597. E-mail address: [email protected] Andrzej Massel / TRA2018, Vienna, Austria, April 16-19, 2018
INFRASTRUCTURE AND OPERATION – RESEARCH ON UTILISATION OF MAXIMUM TRAIN SPEED PROFILE.
Nomenclature l distance Vc commercial speed Vs average start-to-stop speed V0 max average maximum line speed (harmonic mean)
1. Introduction
Infrastructure is the key subsystem of the railway transport and the basis for services provided by rail passenger and freight train operating companies. One of the essential features of the rail infrastructure is the train maximum speed, being the key factor determining quality and competitiveness of the offer and demand for transport (Schumann, 2013, Garlikowska, 2017). The infrastructure of the new railway line is being designed for specified train speed. In case of the construction of completely new lines it is (relatively) easy to ensure, that the speed is uniform along the entire line. The exceptions are usually in the case of sections passing through urban areas with several constraints resulting from existing land use. However the practice of the European railways shows, that even in the case of the newly-constructed high speed railway lines some variations of the maximum speed occur on particular sections. They are typically related to terrain topography and to the location of long tunnels (with limited cross-section area). The parameters of track geometry on existing, conventional railway lines are usually much more diversified. These differences can be attributed not only to the terrain characteristics, but also to the historic legacy. The European railway network was developed (to large extent) in the XIX century as well in the beginning of the XX century. The railway has proved to be one of the most important factors supporting urban development. Therefore adaptation of the classical railway lines to the contemporary requirements is usually very difficult and it is not possible to obtain desired speed on the full length of the line. The most frequent reason are existing parameters of horizontal curves (radius, length of transitions). The change of these parameters would require significant transversal shift of the track alignment. The paper deals with the relation between the maximum speed on particular railway line and the commercial speed of the trains operated there. The aim of the research is to identify factors influencing actual utilisation of the maximum line speed.
2. Factors influencing utilisation of the maximum line speed
2.1. Infrastructure factors
The maximum speeds are usually diversified on the train route. To characterise them it is necessary to adopt some statistical measures. One of these measures should be the highest maximum speed on analysed section. The importance of this value results from the fact, that it determines the requirements for rolling stock making the full use from the infrastructure capabilities. The differentiation of the maximum speed along the line has significant influence on journey time and, consequently, on line capacity. It is taken into account with the harmonic weighted mean V0 max , calculated according to the formula (1):
∑ = (1) ∑
where Vi max is maximum speed on section of track i, and li is the length of section i. This formula has a very clear physical interpretation. Harmonic weighted mean is a quotient of the total length of the line (or the network) and the sum of theoretical journey times on particular sections with the constant speed. Andrzej Massel / TRA2018, Vienna, Austria, April 16-19, 2018
Moreover, two other characteristics of the maximum speed profile can be considered in the study of the utilisation of the train maximum speed: the number of speed changes per 100 km and cumulative change of the maximum speed.
2.2. Rolling stock factors
There is a diversity of passenger rolling stock operated on the European railways. Some trains are operated as sets of conventional passenger cars hauled with electric or diesel locomotives (loco-hauled trains). However the trains composed of Electric Motor Units (EMUs) or Diesel Motor Units (DMUs) are getting more and more popularity. From operational point of view, the train performance is very important. It is characterised with the maximum speed, but also with the values of train acceleration and deceleration. The higher these values are, the lower are the time losses for acceleration and braking of the train. The most important factors influencing train performance are the power output and arrangement of powered axles. Useful (and frequently used) characteristics for them seem to be power-to-weight ratio and percentage of powered axles.
2.3. Operational factors
The journey times for particular sections of the line and for given train compositions are calculated with dedicated software (so called theoretical train runs). Several parameters have influence on the real values of these times:
• Maximum speeds, permanent and temporary restrictions • Stopping pattern and durations of particular stops • Traction characteristics of the locomotive (or EMU/DMU) • Train weight • The recovery margin.
The recovery margins are included in the working timetable in order to guarantee timekeeping. There are several reasons to implement them, for example temporary speed restrictions due to condition of infrastructure, temporary speed restrictions to assure safety during maintenance works, traffic disturbances related to the passage of other trains, malfunction of traffic control systems, differences in the characteristics of rolling stock and in the train weight. Recommendations concerning recovery margins have been elaborated by the International Union of Railways (UIC) in the 451-1 Leaflet (UIC, 2000). They are based on empirical data. It is recommended to use constant minimum margin (expressed as Xmin/Ykm) and speed-dependent margin. For loco-hauled trains the constant component is defined as 1,5 min per 100 km, while speed dependent component is in the range from 3% for light trains (up to 300 tons) with the speed up to 160 km/h to 7% for trains running more than 200 km/h. For trains operated with motor units (EMUs and DMUs) the constant component is 1min/100km, while speed dependent margin is 3% for trains with the speed up to 140 km/h and 7% for trains with the maximum speed exceeding 250 km/h. Nevertheless it should be remembered, that each infrastructure manager sets own rules for time margins. For example the standard value of margin on the French railway network managed by SNCF Reseau is 4.5 minutes per 100 km and the reduced value (for selected long-distance trains) – 3 minutes per 100 km (ETR, 2016). In Poland the standard margin is 3 minutes per 100 km for express trains (EC, EN, EI and EX categories), 4 minutes per 100 km for fast trains (MH, MM and MP categories) and 5 minutes per 100 km for other passenger trains. Moreover allowances in railway scheduling can be optimised, for example by implementing dwell time allowances at selected stations (Rudolph, 2003).
Practical measure for assessment of railway offer in passenger traffic is the value of commercial speed Vc, which is calculated according to the formula (2):
= (2) ∑ ∑ where l is the length of train route, tr are the journey times on consecutive sections and ts are the stopping times. Moreover the start-to-stop average speeds Vs are often calculated for all sections of train run between consecutive stops. It is noteworthy that the start-to-stop train speeds are the basis for train classification in the World Speed Survey, published bi-annually in Railway Gazette International (Hartill, 2017).
Andrzej Massel / TRA2018, Vienna, Austria, April 16-19, 2018
Fig. 1 The ED250 EMU of PKP Intercity at Cracow station
3. Utilisation of the train maximum speed in Poland
At first step, the utilisation of the maximum speed has been researched for the qualified trains serving long-distance routes in Poland. The official infrastructure and timetable data from PKP PLK were used for the analysis of start- to-stop runs of Express Intercity Premium (EIP) trains operated with ED250 EMUs of PKP Intercity. The train data have been extracted from the 2015/2016 timetable, valid from 13 December 2015. The following parameters have been listed for each start-to-stop section:
• Length of the section according to Appendix 2.6 to Regulations concerning allocation and use of train paths on available railway lines by licensed railway undertakings within timetable 2015/2016 • Average maximum speed V0 max calculated as harmonic mean according to Appendix 2.1P • Maximum speed on the section Vmax • Journey time for the fastest train • Start-to-stop average speed • Speed utilization ratio.
The relevant infrastructure and rolling stock data have been compiled for each start-to-stop section. All sections of the network operated with EIP trains were taken into account apart from very short sections in Tri-City (Gdansk, Sopot, Gdynia), Warsaw and Upper Silesia (Katowice – Bielsko-Biala, Katowice – Gliwice). In total 12 sections and 24 start-to-stop runs in both directions have been researched. The longest section (290.2 km) was from Warsaw West station to Cracow (see Fig.1), while the shortest – from Sosnowiec to Katowice (8,8 km). Differentiation of the maximum train speed can be illustrated using the example of the section of E65 main line between Warsaw East station and Ilawa Glowna station. This is conventional railway line, which has been upgraded recently. The current maximum speed is 160 km/h (will be lifted to 200 km/h after installation of ETCS level 2 system), however the speed has to be reduced in some locations due to geometry. Therefore the harmonic mean value of speed on this section equals to 145,3 km/h. The highest value of average maximum speed (V0 max ) on the Polish railway network is in force for train runs on Central Trunk Line section between Wloszczowa Polnoc and Zawiercie (191,1 km/h). The trains operate at the Andrzej Massel / TRA2018, Vienna, Austria, April 16-19, 2018
constant speed of 200 km/h there and only exception is the short section close to Zawiercie station. Therefore the highest start-to-stop ( Vs) speeds are achieved on this section: 167,2 km/h from Zawiercie to Wloszczowa Polnoc and 160,8 km/h in the opposite direction. The present values of maximum line speed and average train speeds on particular sections reflect the gradual improvement of railway infrastructure condition in Poland (Massel, 2014).
Table 1. EIP train runs on the Polish railway network (timetable valid from 13 December 2015). From To Distance Harmonic Max. Time ( t) Start-to-stop Speed (l) [km] mean speed [min] average utilization (V0 max ) (Vmax ) speed ( Vs) ratio [km/h] [km/h] [km/h] Warszawa Wsch. Ilawa Gl. 204,7 145,3 160 93 132,1 0,909 Ilawa Gl. Warszawa Wsch. 204,7 145,1 160 93 132,1 0.910 Ilawa Gl. Malbork 68,9 144,8 160 33 125,3 0,865 Malbork Iława Gl. 68,9 144,8 160 33 125,3 0,865 Malbork Tczew 18,4 125,6 160 11,5 95,8 0,763 Tczew Malbork 18,4 125,6 160 11,5 95,8 0,763 Tczew Gda ńsk Gl. 31,9 148,2 160 16 119,5 0,807 Gdansk Gl. Tczew 31,9 148,2 160 16,5 115,9 0,782 Warszawa Zach. Krakow Gl. 290,2 148,2 200 130 133,9 0,904 Krakow Gl. Warszawa Zach. 290,2 148,4 200 132,5 131,4 0,885 Warszawa Zach. Wloszczowa Pln. 180,9 162,8 200 77 140,9 0,866 Wloszczowa Pln. Warszawa Zach. 180,9 162,1 200 75 144,7 0,892 Wloszczowa Pln. Zawiercie 69,7 191,1 200 26 160,8 0,841 Zawiercie Wloszczowa Pln. 69,7 191,1 200 25 167,2 0,875 Wloszczowa Pln. Sosnowiec Gl. 105,0 156,6 200 45,5 138,4 0,884 Sosnowiec Gl. Wloszczowa Pln. 105,0 156,5 200 46 136,9 0,875 Sosnowiec Gl. Katowice 8,8 92,2 100 8,5 62,4 0,676 Katowice Sosnowiec Gl. 8,8 95,1 100 9 58,9 0,619 Warszawa Zach. Czestochowa Str. 246,8 148,2 200 110,5 134,0 0,904 Czestochowa Str. Warszawa Zach. 246,8 147,8 200 113 131,0 0,887 Czestochowa Str. Opole Gl. 90,6 124,3 140 51,5 105,5 0,849 Opole Gl. Czestochowa Str. 90,6 123,2 140 52 104,5 0,848 Opole Gl. Wroclaw Gl. 81,7 148,1 160 38 129,0 0,871 Wroclaw Gl. Opole Gl. 81,7 147,8 160 38 129,0 0,866
Very good correlation ( r=0,969) exists between the average maximum speeds v0 max and start-to-stop train speeds vs. The following regression equation can be formulated for the Polish EIP train performance (3):
= 0,965 ∗ − 15,4 (3)
4. Maximum speed vs start-to-stop speed on the European railways
4.1. Data collection
The representative database covering the infrastructure data and rolling stock data for intercity train services in various European countries (Austria, France, Germany, Italy, Poland, Spain) has been prepared. It covered three types of train start-to-stop runs:
• Train passages entirely using high speed lines, • Train passages using high speed lines and conventional line sections, • Train passages on conventional rail network.
Andrzej Massel / TRA2018, Vienna, Austria, April 16-19, 2018
This paper deals with the train runs on the high speed lines. The relevant characteristics of the European high speed trains are listed in Table 2.
Table 2. Rolling stock characteristics – high speed trains. Country Train type Train Power Max. No of No of Power-to- Powered weight output speed axles powered weight ratio axles [t] [kW] [km/h] axles [kW/t] [%] Austria Railjet 417,2 6400 230 32 4 15,3 0,125 France TGV Duplex 380,0 8800 320 26 8 23,2 0,308 Germany ICE 2 412,0 4800 280 32 4 11,7 0,125 Germany ICE 3 409,0 8000 330 32 16 19,6 0,500 Germany ICE T 402,0 4000 230 28 8 10,0 0,286 Italy ETR 500 598,0 8800 300 52 8 14,7 0,154 Italy ETR 1000 500,0 9800 360 32 16 19,6 0,500 Spain 100 392,0 8800 300 26 8 22,4 0,308 Spain 102 322,0 8000 330 21 8 24,8 0,381 Spain 103 425,0 8800 350 32 16 20,7 0,500
The compilation of selected high speed train runs on the European railway network is presented in Table 3.
Table 3. High speed train runs on European railways (2015/2016 timetable). From To Distance Harmonic Max. Time (t) Start-to-stop Speed (l) [km] mean speed [min] average utilization (V0 max ) (Vmax ) speed ( Vs) ratio [km/h] [km/h] [km/h] Paris Lyon. Lyon Part Dieu 429,7 259,5 300 118 218,5 0,842 Paris Lyon Marseille 750,2 276,9 320 185 243,3 0.879 Paris Montp. St. Pierre des Corps 221,1 268,0 300 58 228,7 0,853 Paris Montp. Le Mans 202,1 259,5 300 54 224,4 0,865 Paris Nord Lille Europe 225,5 268,2 300 59 229,3 0,855 Madrid Atocha Valencia 390,8 270,6 300 98 239,3 0,884 Madrid Atocha Cordoba 343,6 237,3 300 100 206,2 0,869 Cordoba Sevilla 126,7 222,0 250 43 176,8 0,796 Cordoba Malaga 168,9 270,9 300 48 211,1 0,779 Madrid Atocha Zaragoza 306,7 277,3 310 75 245,5 0,885 Madrid Atocha Barcelona Sants 621,0 278,0 310 150 248,4 0,894 Madrid Valladolid 179,1 251,8 300 54 199,0 0,790 Chamartin Berlin-Spandau Wolfsburg 170,3 238,5 250 54 189,2 0,794 Siegburg Frankfurt Flugh. 143,3 285,1 300 38 226,3 0,794 Roma Termini Napoli Centrale 222,4 245,9 300 70 190,6 0,775 Roma Termini Milano Centrale 567,3 236,1 300 175 194,5 0,824 Roma Termini Firenze Campo 257,1 232,5 250 78 197,7 0,851 Roma Tiburtina Firenze SMN 256,7 222,6 250 81 190,1 0,854 Firenze SMN Bologna Centrale 91,5 243,4 300 35 156,8 0,644 Bologna Centrale Milano Centrale 216,7 253,7 300 62 209,7 0,827 Milano Centrale Torino PN 147,2 216,5 300 60 147,2 0,680
The subject of maximum speed on the newly built infrastructure is highly controversial. There is no uniform approach in determination of the maximum speed on high speed lines. Therefore some railway lines in Europe are operated at 250 km/h, some at 300 km/h and some at 320 km/h. Discussing the issue of ‘optimum speed’ Lebeuf Andrzej Massel / TRA2018, Vienna, Austria, April 16-19, 2018
(2014) suggests two criteria at the crossroads between environment and economy: an environmental criterion and socioeconomic criterion. As a rule, the highest values of average maximum speeds (V0 max ) on particular networks usually concern the sections, which are fully located on high-speed lines and do not include entrance to large railway nodes. For example the average weighted maximum speed on the Siegburg – Frankfurt Flughafen section on the Cologne – Frankfurt line exceeds 285 km/h, while the top speed is 300 km/h. As far as start-to-stop average speeds ( Vs) is concerned, it is noteworthy, that their highest values are achieved in case of very long intercity runs without intermediate stops, for example:
• Madrid – Barcelona ( Vs=248,4 km/h), • Madrid – Zaragoza ( Vs=245,4 km/h), • Paris – Marseille ( Vs=243,3 km/h), • Madrid – Valencia ( Vs=239,3 km/h).
The performance of the rolling stock used for mentioned services is extremely good. Power-to-weight ratio for 102 (Pato) and 103 series (Velaro) of the Spanish railways (RENFE) exceeds 20 KW/ton. Similarly the power output of the French (SNCF) TGV Duplex EMUs is more than 23 kW per ton. For such long runs (the distance between Paris and Marseille is around 750 km), time losses for acceleration at the start of the journey and for braking at its end are relatively minor in comparison to the essential part of the run at the speed of 300 km/h or even more.
The best utilisation of average maximum speed can be seen in case of high speed lines in Spain (0,894 for Madrid – Barcelona route) and in France (0,879 for Paris – Marseille route). The most favourable speed ratio for the Italian speed network can be observed on Rome – Florence railway line ( Direttissima ). For analysed set of data from the European high speed railways, significant correlation between V0 max and Vs exists (r=0,858):
= 1,157 ∗ − 84,6 (4)
High speed lines - Vomax - Vs relation 260
250
240
230
220
210
Vs Vs [km/h] 200
190
180
170
160 200 210 220 230 240 250 260 270 280 290 300 V0max [km/h]
Vs [km/h] regression
Fig. 2 The relation between average maximum line speed and start-to-stop train speed Andrzej Massel / TRA2018, Vienna, Austria, April 16-19, 2018
Fig. 3 ETR1000 EMU on Rome – Milan non-stop service after arrival to destination
5. Results
The analysis confirmed very good correlation between the average maximum line speed and the train commercial (start-to-stop) speed. The top values of the commercial to (average) maximum speed ratio for high speed lines is in the case of Madrid – Barcelona (0,894) and Paris – Marseille routes (0,879). In case of conventional lines values exceeding 0,9 have been identified for some sections operated with ED250 trainsets in Poland (Warsaw East – Ilawa).The differences between start-to-stop average speeds and average maximum speeds result from time losses due to train acceleration and braking at the beginning and the end of each run but also in all locations, where maximum speed changes. Moreover timetable recovery margins (according to UIC 451-1 Leaflet) are added to guarantee timekeeping. The best utilisation of line maximum speed is in the case of long sections (300 km or more) passed without intermediate stops. On such long section the influence of acceleration and braking is relatively minor. The utilisation of maximum speed is negatively influenced by significant differentiation of the speed profile (frequent and large changes of speed along the line). The most effective utilisation of line capabilities is in the case of Electric Motor Units (EMUs) with distributed power and high power-to-weight ratio (more than 20 kW per ton). The results of the study show clearly, that the selection of passenger rolling stock for particular route can have huge impact on its day-to-day operation. Therefore it is very important to take the infrastructure characteristics (gradients, maximum speed profile) into account at the stage of drafting specifications for the rolling stock to be used on particular route. Similarly it is important to carry out in-depth analysis of rolling stock performance as a part of feasibility study for construction of the new railway infrastructure or modernisation of existing one. This is important field of applicability of the results of the study as the tool to compare large number of various variants of the future infrastructure investment. It allows to check, how the speed profile for designed alignment will be “consumed” in practice with the rolling stock to be used and with the planned stopping pattern. Further research is needed to assess the utilisation of the maximum speed by trains operating on conventional railways. Andrzej Massel / TRA2018, Vienna, Austria, April 16-19, 2018
6. References
ETR, 2016. 1980-2020: 40 Jahre Entwicklung des französichen Eisenbahnnetzes. ETR Nr. 1+2, 32-38. Garlikowska, M., Use of Time While Travelling by Passenger Trains – Requirements and Needs of Passengers. Problemy Kolejnictwa (Railway Reports), 2017, Vol. 175., 21-28. Hartill, J., 2017. Italy joins the premier speed league. World Speed Survey. Railway Gazette International, July 2017, 28-31. Lebeuf, M, 2014. High-speed rail. Le cherche midi, pp. 506. Massel, A., 2014. Improvement of railway infrastructure in Poland. TTS - Technika transportu szynowego 2014, nr 6, 2-6. Massel, A., 2015. Gradual implementation of high-speed operation in Poland. UIC Highspeed. 9 th World Congress on High Speed Rail. Tokyo, July 2015. Rudolph, R., 2003. Allowances and Margins in Railway Scheduling. Proceedings of the 6 th World Congress on Railway Research, Edinburgh, Sept.-Oct. 2003. Schumann, T., 2013. Passenger Demand for a High-speed Network Across Europe. Problemy Kolejnictwa (Railway Reports), 2013, Vol. 161., 67-86. UIC, 2000. Leaflet UIC 451-1 OR. Timetable recovery margins to guarantee timekeeping – Recovery margins.