Alain Croset SNC-Lavalin and New Traction Power Technologies to Improve David E Anderson Department of Transport Victoria the Melbourne Tram Network NEW TRACTION POWER TECHNOLOGIES TO IMPROVE THE MELBOURNE TRAM NETWORK David Edward Anderson Alain Croset BE (Hons) HND Department of Transport Victoria SNC-Lavalin SUMMARY The Melbourne Tram Network is the largest in the world with 250 kilometres of track and 490 trams. The city’s fast-growing population has triggered a new approach to improve sustainability. The New Rolling Stock Program managed by Department of Transport Victoria included an out-of-the-box option analysis for traction power supply. It was undertaken to address forecast patronage growth and retirement of the high floor tram fleet while increasing the energy efficiency drawn from the Traction Power Supply. The effort included simulation of many combinations of standard and new technologies both on-board and wayside to assess their outcomes at both location and network levels. To avoid drastically increasing energy consumption, introducing new vehicles with on-board energy storage and optimising sectioning of the electrical distribution was found essential for a substantial improvement in energy management. The proposed upgrades enable better recovery of braking energy, minimising losses through local on-board re-use preference over transferring it to other trams. It means capital minimisation upgrades to key power network assets. To complete the improvement, an innovative energy management of the on-board energy systems will be required from tram suppliers to optimise both the on-board energy saving and the overall Traction Power Supply efficiency. Optimising upgrades necessary to supply the additional and higher passenger capacity vehicles included some additional substations. However, in some specific areas, side feeders and wayside energy storage systems were a cost-efficient part of the solution to avoid substation land acquisition. Simulations showed that even with the increase in passengers carried, the network energy consumption would be no greater than the present-day level. These systemic and holistic upgrades will reduce investments needed to adapt the network to the population growth in the future. 1. INTRODUCTION network. These new higher capacity, low floor trams will replace the existing high floor fleet The Melbourne Tram Network (MTN) is the which are approaching their end of life. largest in the world with 250 kilometres of double track and 490 trams. Due to strong Trams on the MTN are 75 per cent operated in population growth in recent years the network multiple-use road environments including cars is now reaching capacity. Projections estimate and cyclists. 25 percent comprises segregated that by 2051, Melbourne’s current population of tram only operation sections. Powered by the 5 million people will increase to 7.9 million. To Traction Power Supplies through overhead support this level of growth, the public lines, trams require energy for: transport system must be upgraded to provide increased capacity and additional routes › Traction / vehicle propulsion; and provided, to align with population growth areas. › Auxiliary equipment like passenger information; heating and air-conditioning. To improve network capacity, the New Rolling Stock Program managed the Department of Technological improvements available have Transport Victoria, will introduce approximately resulted in key on-board systems (such as 250 Next Generation Trams (NGT) to the traction and braking systems) being more energy efficient than those fitted to previous AusRAIL PLUS 2019 3 – 5 December, Sydney Alain Croset SNC-Lavalin and New Traction Power Technologies to Improve David E Anderson Department of Transport Victoria the Melbourne Tram Network generations of rolling stock. Combined with 2.1 Auxiliary power consumption the use of lighter materials for vehicle The high floor trams to be retired are fitted with construction, this results in the traction / minimal on-board equipment. Maximum vehicle propulsion component consuming less auxiliary power draw varies between 4 kW and than previous generations of vehicles, per unit 32 kW dependent on vehicle length and HVAC length. provision. Modern on-board equipment and features In comparison, new modern trams are fully air- provide an improved passenger experience, conditioned and fitted with modern on-board including air-conditioning, higher acceleration equipment. They are expected to have a performance, passenger information systems maximum auxiliary power draw of 50 kW which and many other sub-systems that did not exist represents an increase of 52% from the longer 20 or 30 years ago. These improvements high floor trams to be retired and 11 times partially offset the reduction in the traction / more than the shorter variant. propulsion system energy consumption. In addition to the introduction of new trams, to 2.2 Traction power consumption further increase network capacity service High floor trams have a maximum traction frequency will increase on high demand routes power of 420 kW for the short variant and 486 increasing energy consumption on these kW for the longer variant. routes. In comparison, new modern trams with higher 2. PROBLEM STATEMENT passenger capacity fitted with standard The introduction into service of new modern traction-braking technology would have a trams with increased service frequency will maximum power of 550 kW which represents require a significant additional amount of an increase of 30% from the shorter high floor energy to be delivered to the network. The trams and 15% from longer high floor trams as main goal of the project was to identify the right shown in the vehicle power curves for each group of like trams as shown in Figure 1. solutions to achieve this in a sustainable and cost-effective way. AusRAIL PLUS 2019 3 – 5 December, Sydney Alain Croset SNC-Lavalin and New Traction Power Technologies to Improve David E Anderson Department of Transport Victoria the Melbourne Tram Network Figure 1 - Vehicle Power Curve 3. BASELINE ENERGY CONSUMPTION energy consumption of all tram types used on the Melbourne Tram Network. This model was To ensure rolling stock can operate at full adapted from the methodology developed by performance, the traction power supply the Optimal Strategy to Innovate and Reduce network must be able to provide the required Energy Consumption In Urban Rail Systems maximum power and energy. While this (OSIRIS) rail research project (Iordache 2013). characteristic is available from tram supplier Completed in December 2014, OSIRIS datasheets, the energy consumed by the consisted of 17 project partners including rolling stock over the time is not readily major stakeholders such as railway available. As such the team had to establish manufacturers, public transport operators and these figures for the overall consumption of the universities. Its goal was to enable a reduction network. The Department of Transport Victoria in the overall energy consumption within owns a full TrainOps® model of the Melbourne Europe’s urban rail systems by 10% from 2012 Tram Network. This model has been jointly levels by 2020. developed by the Department and LTK using LTK’s operation and electrical network Workshop 1 of the OSIRIS project identified a simulation software TrainOps®. Using the method for standardising duty of rolling stock results of network simulation, the energy and building energy consumption figures. consumption of the existing network has been Adapting this methodology, the energy evaluated and compared with the energy bill. consumption of all tram types used on the MTN was established. Single vehicle runs To determine the current energy consumption were simulated on the same chosen route, with of the overall Melbourne Tram Network, a traction and auxiliary consumption integrated model was developed to characterise the and linearised per kilometre which enabled the AusRAIL PLUS 2019 3 – 5 December, Sydney Alain Croset SNC-Lavalin and New Traction Power Technologies to Improve David E Anderson Department of Transport Victoria the Melbourne Tram Network maximum energy consumption for every tram 4.1 Engineering Process class to be determined. Rather than addressing the increase in power The whole network was then simulated using and the energy consumption by adding only the existing rolling stock to establish the substations, an innovative solution mitigating energy consumption of the then present 2018 standard techniques (substations, feeders, re- services. The network was then simulated sectioning) has been produced. This includes using new trams operating at a higher service more recent proven technologies like on-board frequency to establish the baseline energy and wayside energy storage. consumption for complete low-floor fleet in the An overview of the process is shown on the year 2031. The total MTN energy consumption chart of Figure 2. At first the team conducted a would rise from 2018 operations with existing desktop analysis of the Traction Power ageing fleet of 153 GWh to 200 GWh for 2031 network, starting with the existing network and all low-floor fleet without OESS at the then incorporating the route upgrades and the increased service frequency planned. This is new tram acquisitions. Based on the existing an increase of 30 per cent, assuming no TrainOps® model of the MTN, scenarios wayside or on-board energy storage systems. combining standard and new technologies have been modelled and then compared under 4. Engineering