【正文】 ve less impact on the environment. As 197。kerman (2011) states, speci?c greenhouse emissions concerning propulsion and fuel production in electric trains, will be lower than emissions from other kinds of traction. Overhead lines have an additional advantage over other groundlevel located systems that supply energy: the former mechanism is both safer in terms of accidental contacts of people or animals, and have fewer voltage restrictions than the latter one, owing to the elevation over the ground. This fact allows railway panies to use powerful lootives and more traf?c over the tracks (see Hartland, 2008。 Montesinos and Carmona, 2007).In spite of the advantages of using overhead lines, their deployment along the railway tracks is a very plex design process. This plexity can be analysed from four different perspectives.First of all, many elements have to be considered so as to electrify a track stretch of several kilometres in length. The overhead contact line, hereinafter also called catenary, is assembled considering a range of spans of about 60 m in length, normally between 15 and 20 (Montesinos and Carmona, 2007). If each of them is supported by a pair of poles, more than 30 poles per km in twoway standard tracks are needed. At railway stations, the number of tracks is increased and the space is limited, so poles are replaced with portal frames, thus allowing simultaneous support for multiple closelocated catenaries through a single structure. As an example, Fig. 1 illustrates the high number of portal frames in a railway station.Secondly, the deployment process involves several plex and critical tasks:1. Placing structures along the track stretches. This may include a ground projection of the elements and an analysis of geographical, climatic, and terrain conditions.2. Designing support elements, like poles and portal frames, in order to withstand the main catenary infrastructure ponents (wires and cantilevers). Moreover, these supporting elements must deal with extreme conditions, like strong winds and ice overload.Thirdly, there are many experts that take part in the design process (De Bruijn and Veeneman, 2009). Every previously mentioned task requires knowledge from different ?elds, such as topography, architecture, structural calculus and drawing. Moreover, technical security and legal normative have to be considered throughout the process. Therefore, every task is assigned to a different expert of each ?eld. From this point of view, the plexity of the design process lies in the variety of knowledge sources, and it bees worse due to the dif?culty and slowness of munication among all the experts.Fourthly, as the experts taking part in the process belong to different panies, the railway pany must deal with several outsourced enterprises within a rail work project. This fact results in a hard munication among them, because every pany has its own organization, interoperability protocols, and interfaces (Panetto and Molina, 2008). Moreover, when concerning a cross country project, several railway panies get involved in it, so patibility issues must be take into account (Midya and Thottappillil, 2008).The paper is organized as follows. Section 2 describes the stages involved in the design process of deploying overhead lines within a project. In Section 3, the algorithm to design and calculate a single catenary support structure is 4 presents the high productivity software tool developed to perform the whole design process ef?ciently. Section 5 analyzes the tool performance of resolving multiple catenary support structures. Section 6 includes some results, validations, and discussions about the tool. And, ?nally, Section 7 shows the main conclusions of the paper.2. The process of designing and calculating the railway catenary infrastructureThe design and calculation of the railway catenary infrastructure is a very plex process, as it is described in Kiessling et al. (2009). It involves several stages that need to be acplished in order to obtain a valid solution. Every stage of the process requires speci?c knowledge from different ?elds, so that different experts have to take part in it. These experts usually belong to different outsourced panies, that must deal with the railway pany so as to agree on the requirements, costs, quality, security and technical aspects, and legal issues.In this section, we present the stages of this design process with further detail, based on three sources: railway pany experts, the design planning process described in Kiessling et al. (2009), and previous works (Carretero et al., 2003。 Saa et al.,2012). Fig. 2 shows all the steps as they are carried out curently, and the experts involved in each one. As may be seen, several rapports have to be established between the different experts.– The manager of a rail work project asks for the design of the railway catenary infrastructure. He must de?ne several requirements like the ground features, the height of the catenary points, and how and where the catenaries are held. This de?nition is sent to the design engineer.– The design engineer provides a possible design solution for every structure within the project. Each one must be valid from a geometrical point of view. At this stage, many elements belonging to the railway inventory (foundations, poles,lintels, cantilevers, wires, etc.), have to be considered so as to generate possible binations that ?t the requirements speci?ed by the project manager. When consulting the inventory through the railway pany, the aim is to provide minimum cost design solutions. Costs are de?ned by weight, type of material, and manufacturing efforts. All the binations that can be proposed make the process more plex and more expensive, because speci?c knowledge for the design experts part is needed.– At this point, a rapport between the railway pany and the design outsourced pany is established. The solutions provided by the design engineer must be checked