Computers & Operations Research 36 (2009) 1461 – 1477 www.elsevier.com/locate/cor Location of infrastructure in urban railway networks  Ángel Marín a , ∗ , Ricardo García-Ródenas b a Universidad Politécnica de Madrid, Escuela Técnica Superior de Ingenieros Aeronáuticos, Plaza Cardenal Cisneros, 3, 28040 Madrid, Spain b Universidad de Castilla La Mancha, Escuela Superior de Informática. Paseo de la Universidad, 4. 13071, Ciudad Real, Spain Available online 10 March 2008 Abstract The location of the infrastructure of the Rapid Transit Network considers at upper level a list of potential transit corridors and stations on the basis of its own constraints, so the network design is modelled on a discrete space of alternatives. At lower level the alternatives are evaluated based on the route and mode user decisions. The optimization objectives are to maximize the transit demand and minimize the private travel time, considering the user’s behavior, the physical network, budget constraints and the network design constraints. The design criteria are considered as location constraints, they have been traditionally defined by node and link compatibilities defining lines, but we define a new location constraints based in to minimize the number of routing intersections. The demand mode splitting constraints may be defined by all or nothing mode assignment or like it is proposed by us in this paper by Logit distribution. The models defined with the above alternatives are large integer multicommodity flow network design problems with side constraints. These sets of alternatives are computationally studied to obtain conclusions. The experiments are presented using two networks, a small network and a medium size network, simulating the city of Seville.  2008 Elsevier Ltd. All rights reserved. Keywords: Urban train station and alignment location; Network design; Rapid Transit Networks; Mode Logit distribution 1. Introduction The increase of mobility caused by the growth of traffic problem in city centers is one of the reasons why new rail transit networks have been constructed. Some cities have constructed traditional underground metro systems, surface rail rapid transit, and light rail transit, while in other cities, existing networks have been expanded. The planning of such systems is complex, involving decisions relating to the topological configuration, number and location of lines and stations, the frequency of lines, fares and interchange parking, etc. The two core issues that have been studied in literature are: (a) The “metro” transit line location inside urban–suburban zones (see [1,2]) and (b) the number and the locations of the station in a given line (see [3]). The major criticism of these models is that the user’s behavior is not explicitly introduced. It is implicitly assumed that a “good” transit network will promote its use. The first attempt to take user’s behavior into account is given in Bruno et al. [4], where the mode choice is formulated using an all-nothing mode assignment. Recently, Laprote et al. [5] introduced the Logit demand to model the choice of only one transit line.  Partially supported by Spanish Ministerio de Fomento: Research Project 70029/T05, and by Spanish Ministerio de Educación y Ciencia: Research Project TRA2005-09068-C03. ∗ Corresponding author. E-mail addresses: angel.marin@upm.es (Á. Marín), Ricardo.Garcia@uclm.es (R. García-Ródenas). 0305-0548/$ - see front matter  2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.cor.2008.02.008