Antonio Fernández

Universidad Pontificia Comillas | UPCO · https://www.iit.comillas.edu/personas/antoniof

Regenerated energy has the potential to produce great energy saving figures in railway operation. However, in DC systems, regenerated energy cannot be harnessed completely. The presence of rectifier filters does not allow returning energy from the railway system to the utility grid. Therefore, the regenerated energy that cannot be consumed by other...

Policies for reducing CO2 and other GHG emissions have motivated an increase in electrification in metropolitan areas, mandating reductions in energy consumption. Metro systems are keystone contributors to the sustainability of cities; they can reduce the energy consumption of cities through the use of the economic driving parameters in their onboa...

Eco-driving is a keystone in energy reduction in railways and a fundamental tool to contribute to the Sustainable Development Goals in the transport sector. However, its results in real applications are subject to uncertainties such as climatological factors that are not considered in the train driving optimisation. This paper aims to develop an ec...

The transport capacity of an urban railway line can be increased in many different ways. For planners and infrastructure managers it is vital to have all the tools available that allow choosing the most cost-effective solution among all the possibilities. This selection process can be complex sometimes and deciding how the available capacity should...

Installing Energy Storage Systems (ESSs) to improve electrical infrastructures of Direct-current (DC) railway systems implies considerable investments that must be assessed carefully. Therefore, it is often necessary to combine detailed railway simulations and decision support mechanisms. Unfortunately, most examples in the literature deal with thi...

This paper deals with the problem of finding the optimal location and sizing of Energy Storage Systems in DC-electrified railway lines. These devices increment the use of the regenerated energy produced by the trains in the braking phases, as they store the energy to later provide to the catenary the excess of regenerated energy, that otherwise wou...

The installation of wayside Energy Storage Systems (ESSs) in DC-electrified railway systems is one of the main measures to improve their energy efficiency. They store the excess of regenerated energy produced by the trains during the braking phases and give it back to the system when necessary. Nevertheless, the big cost of the associated installat...

The new Automatic Train Operation (ATO) system over the standard European Rail Traffic Management System (ERTMS) will specify the requirements that an automatic train driving system must fulfil in order to be interoperable. The driving is defined by target times located along the journey that are received from the trackside system. Then, the on-boa...

In addition to energy consumption, DC railway operators must also pay for the demand charge. This term of the electricity bill has not been studied in detail in the literature and penalizes power peaks. The big fluctuations on the power demand which characterize railway systems make the demand charge important for railway operators. This paper stud...

Nowadays, one of the strategies that are being applied in DC railway networks to improve energy efficiency is the installation of Reversible Substations or Energy Storage Systems. The assessment of their impact on the network consumption is typically based on simulation. The accuracy of the results provided by the simulations relies on the accuracy...

Improving the railway electrical infrastructure of DC railway systems with the installation of Reversible Substations (RSSs) or Energy Storage systems (ESSs) implies considerable investments that must be carefully studied. In this decision-making process, the use of electrical multi-train simulators is fundamental, in order to make accurate estimat...

The installation of wayside Energy Storage Systems (ESSs) in DC-electrified railway systems is one of the main measures to improve their energy efficiency. They store the excess of regenerated energy produced by the trains during the braking phases and give it back to the system when necessary. Nevertheless, the big cost of the associated installat...

Eco-driving is one of the most promising methods to reduce the energy consumption of existing railways. Considering the practical situation in complex railway lines, this article proposes a new multi-objective searching algorithm to obtain the set of most efficient speed profiles in train journey for each combination of arrival and intermediate tim...

Eco-driving is one of the most important strategies for significantly reducing the energy consumption of railways with low investments. It consists of designing a way of driving a train to fulfil a target running time, consuming the minimum amount of energy. Most eco-driving energy savings come from the substitution of some braking periods with coa...

Improving the railway electrical infrastructure of DC railway systems with the installation of Reversible Substations (RSSs) or Energy Storage systems (ESSs) implies considerable investments that must be carefully studied. In this decision-making process, the use of electrical multi-train simulators is fundamental, in order to make accurate estimat...

Transport is a main source of pollutants in cities, where air quality is a major concern. New transport technologies, such as electric vehicles, and public transport modalities, such as urban railways, have arisen as solutions to this important problem. One of the main difficulties for the adoption of electric vehicles by consumers is the scarcity...

Nowadays, one of the strategies that are being applied in DC railway networks to improve energy efficiency is the installation of Reversible Substations or Energy Storage Systems. The assessment of their impact on the network consumption is typically based on simulation. The accuracy of the results provided by the simulations relies on the accuracy...

Eco-driving is an energy efficient traffic operation measure that may lead to important energy savings in high speed railway lines. When a delay arises in real time, it is necessary to recalculate an optimal driving that must be energy efficient and computationally efficient. In addition, it is important that the algorithm includes the existing un...

Nowadays, railway transport capacity is an important bottleneck for many railway operators that face its ever-increasing demand. This poses a challenge to existing lines as operation under conditions close to saturation tends be unstable. Capacity in urban railway systems depends largely on dwell times at platforms, but capacity measures proposed i...

Eco-driving is a traffic operation measure that may lead to important energy savings in high speed railway systems. Eco-driving optimization has been applied offline in the design of commercial services. However, the benefits of the efficient driving can also be applied on-line in the regulation stage to recover train delays or in general, to adapt...

In addition to energy consumption, DC railway operators must also pay for the demand charge. This term of the electricity bill has not been studied in detail in the literature and penalizes power peaks. The big fluctuations on the power demand which characterize railway systems make the demand charge important for railway operators. This paper stud...

Among the different approaches for minimising the energy consumption of mass transit systems (MTSs), a common concern for MTS operators is the improvement of the electrical infrastructure. The traffic on the lines under analysis is one of the most important inputs to the studies devoted to improving MTS infrastructure, since it represents where and...

The electrical infrastructure of DC-electrified mass transit systems (MTSs) is currently under review. The improvement of MTS infrastructure is commonly tackled by means of optimisation studies. These optimisers usually take large times to obtain their solutions, mainly due to the traffic scenarios that must be taken into account. The optimisation...

In CBTC (Communications-Based Train Control) operated metro lines, headway can be reduced by taking advantage of the system's train-track continuous communication, thus increasing transport capacity. When a train runs close enough to the preceding one, a tracking algorithm is triggered to control the distance between the trains. The following train...

Metropolitan railway operators’ strategic plans include nowadays actions to reduce energy consumption. The application of ecodriving initiatives in lines equipped with automatic train operation (ATO) systems can provide important savings with low investments. Previous studies carried out under the ATO framework have not considered the main uncertai...

The application of ecodriving strategies leads to important energy savings in high speed railway systems. Ecodriving techniques are usually offline implemented in the design of commercial services. However, efficient driving can also be online recalculated to regulate the deviations from the schedule of the train. In this paper, a dynamic multi-obj...

One of the main priorities for metro line operators is the reduction of energy consumption, due to the environmental impact and economic cost. The new moving block signalling system CBTC (Communication Based Train Control) is being installed in order to increase the transport capacity of new metro lines, and to upgrade lines equipped with the forme...

Energy and environmental sustainability in transportation have become crucial in recent decades. According to the Intergovernmental Panel on Climate Change?s Fifth Assessment Report (AR5), the transport sector accounted for 27% of the final energy use and 6.7 gigatons of CO2 direct emissions in 2010, with baseline CO2 emissions projected to approxi...

For transportation in large cities, new technologies that impact the operation of metro-transit systems are being developed. The energy efficiency in metro-transit systems is a key topic that is being studied in order to reduce both consumption and costs. A review on approaches to managing the energy recovered from train braking is reported. Then,...

Railway mass transit systems like subways play a fundamental role in the concept of sustainable cities. In these systems, the amount of passengers strongly fluctuates along the day. Hence, in order to provide a proper service without incurring disproportionate energy consumption, operation at different traffic densities is required. The majority of...

One of the strategies for the reduction of energy consumption in railways systems is to execute efficient drivings (eco-driving). This eco-driving is the speed profile that requires the minimum energy consumption without degrading commercial running times or passenger comfort. When the trains are equipped with Automatic Train Operation systems (ATO...

Nowadays one of the main priorities for railways administrations and operators is the reduction of energy consumption, due to its impact on CO2 emissions and economic costs. This is especially important on high speed lines, in expansion in many countries, given that very high levels of consumption are involved. Energy saving strategies focused on t...

Sistema de aprovechamiento de energía eléctrica regenerada por un tren o disponible en catenaria, por parte de un vehículo eléctrico, y procedimiento asociado. Sistema y procedimiento de aprovechamiento de energía eléctrica regenerada durante la etapa de frenado de al menos un tren (1) perteneciente a una red de trenes o disponible en una catenaria...

Railway rapid transit systems are key stones for the sustainability of mass transit in developed countries. The overwhelming majority of these railway systems are direct-current (DC) electrified and several energy-saving techniques have been proposed in the literature for these systems. The use of regenerative-braking in trains is generally recogni...

Energy efficiency is an important concern in for railway administrations and operators. Strategies focused on traffic operation can achieve energy savings in short term and with associated low investments. For that purpose the main strategies are the design of efficient timetables and driving (ecodriving). The ecodriving applies coasting commands (...

This paper presents a simulation-based model for manual driving strategies that will minimize energy consumption for high-speed trains. Specific characteristics of both high-speed lines (HSLs) and manual driving strategies are considered in order to obtain achievable designs that can be tested on commercial services. The proposed design model calcu...

Energy Storage Systems (ESSs) represent one of the main vectors for improving railway electrical systems. Former low reliability rates and life-time are being dramatically improved in recent times due to the intensive research on battery and capacitor technologies. However, little research has been conducted on the optimization of railway system in...

Different strategies are being applied nowadays to minimize energy consumption in Bilbao Underground (Metro de Bilbao). For that purpose, ATO driving commands in Metro de Bilbao have been optimized in order to reduce the consumption of traffic operation, taking into account operational requirements that are observed or even more improved. These ope...

This paper deals with the design of underground rail system timetables that synchronize the movement of trains to allow the energy consumption from substations to be reduced by maximizing the use of regenerative-braking energy. Nowadays, most trains are equipped with regenerative-braking systems and any of this recovered energy not used by on-board...

Traffic operation has a significant impact on energy consumption in metro lines and thus it is important to analyze strategies to minimize it. In lines equipped with Automatic Train Operation systems (ATO), traffic regulation system selects one ATO speed profile on line among a preprogrammed set of optimized speed profiles. Previous works only mini...

This paper presents an equivalent model that allows representing bi-voltage autotransformer-based systems (such as 2x25 kV ac, 2x15 kV ac) as if they were monovoltage systems. This model can be used for symmetrical (such as 2x25-kV 50-Hz systems) and unsymmetrical (such as 12/24-kV 25-Hz systems) configurations. It is based on two simplifying hypot...

Trains equipped with automatic train operation (ATO) systems are operated between stations according to the speed commands they receive from balises. These commands define a particular speed profile and running time, with associated energy usage (consumption). The design of speed profiles usually takes into account running times and comfort criteri...

This paper presents some results obtained with an electric railway simulator. This tool has been mainly developed for studying energy consumptiom in both AC and DC electrified railway systems. Two case studies have been carried out. The first one analyzes a DC electrified underground system, assessing the energy saving related with the introduction...

Reduction in energy consumption has become a global concern, and the EU is committed to reducing its overall emissions to at least 20% below 1990 levels by 2020. In the transport sector measures are focused on planning, infrastructure, modal change, the renewal of vehicles and also programmes for efficient driving. In metro lines equipped with ATO...

This article presents a combined simulation and optimisation technique to optimise the energy consumption of a single manual-driving train service with inter-stations along a High Speed Line. For this purpose, the best energy efficient driving strategies along every stretch between two stations will be simulated with an accurate and detailed train...

Energy usage in electrical railway systems is being studied in order to find technologies and developments for increasing energy efficiency. It is not only an environmental problem, but also concerns railway infrastructures as an economical aspect. The problem is finding which system to invest in for decreasing energy consumption and costs. In this...

Traffic regulation systems of metro lines equipped with Automatic Train Operation (ATO) use a set of pre-programmed speed commands selecting coasting points and brake deceleration. Different speed commands provides different travel times between stations and the regulation system on-line selects and sends to the train one of these commands. Nowaday...

This paper presents a new algorithm and a procedure for the efficient and accurate calculation of braking distances satisfying current safety Standards. One of these Standards is applied in ADIF (Spanish Railway Infrastructure Administrator), for instance, in the design of signalling systems, to locate signals and balises. Following the Standard, b...

MATHEMATICAL PROGRAMMING APPROACH TO UNDERGROUND TIMETABLING PROBLEM FOR MAXIMIZING TIME SYNCHRONIZATION

Traffic simulation models in metro lines are widely used in predictive control algorithms for traffic regulation and robustness analysis of timetables. The simulation results are highly dependent on the uncertainty modelling. The two main parameters in the simulation models are running times and dwell times. In lines operated with ATO systems (Auto...

This paper presents a new traffic regulation model for metro lines based on the optimisation of a cost function along a time horizon. The resulting control actions modify nominal running times and dwell times to compensate timetable and headway deviations. The proposed quadratic programming model is suitable to include the main operation constraint...

This paper presents an optimization procedure to determine the topology of AC railways power supply networks: location and type of the substations, catenaries to be used, location of neutral zones and location of autotransformers in 2×25kV systems. In the proposed procedure, a mixed integer programming problem (MIP) is formulated in order to minimi...

In the design process of a 2x25kV power supply, the location and sizing of autotransformers and the choice of the catenary type are usually two aspects very closely interrelated. As a result, the number of autotransformers can normally be reduced or augmented if the catenary is upgraded or downgraded respectively. In this paper, coupling equations...

A method to study railway power supply systems with AC power distribution networks and DC power feeding is presented in this paper. The aim of this work is to obtain a DC model of the whole system in which AC networks are converted into equivalent DC ones. Relationships between AC and DC quantities on both sides are set using the equations of multi...

This article proposes a predictive traffic regulation model for metro loop lines on the basis of the optimization of a cost function along a time horizon. The regulation strategies typically compensate timetable and headway deviations modifying the train run times. The existing optimization methods are based on simplified traffic models with analyt...

This paper presents an integrated information model for traffic planning, operation and management of railway lines, that has been implemented in the new control centre of the Madrid-Lleida high speed line. The long and medium- term planning information is created with an off-line Planner Tool, generating a Operational Plan in XML format. This Plan...

This paper presents a reduced model of 2×25 kV electrical systems for high speed railways. The structure of both the proposed reduced model and the 1×25 kV system are similar. This reduced model has been developed to be included in a design optimization program of high-speed railways power supply systems. The accuracy of the reduced model is checke...

The design of the electrical supply system of high-speed railway lines involves the selection of the single phase system (one or two active conductors: 1×25 kV or 2×25 kV), the design of the catenary, and the location and sizing of the substations and the autotransformers in case of a 2×25 kV system. The electrical system should be designed so the...

This paper presents a multi-train simulator for railway networks. The main use of this traffic flow simulator is to serve as a test bench for traffic control strategies. The most interesting features of this particular simulator are two: modularity and generality. The traffic flow simulator is build up with three independent components: (1) a signa...

RESUMEN En este artículo se aborda un problema de diseño de horarios para explotaciones metropolitanas con el objetivo de maximizar el aprovechamiento de la energía proveniente de los sistemas de frenado regenerativo. Actualmente, la mayor parte de los trenes están equipados con sistemas de freno regenerativo, recuperando una energía que se emplea...

In bi-voltage systems, the positive voltage is normally established by the standards while the negative voltage can be chosen by the designer. Often the negative voltage is set to the same value used for the positive one in order to simplify the design, the operation and the maintenance. However, using a higher negative voltage can significantly en...