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This paper presents a study about studentification in a small, compact Spanish city. Unlike most of the previously analysed cases, students of this city share flats instead of living in houses in multiple occupancy. The studentification, which is hardly perceptible in the streets or the neighbourhood, becomes a reality in the staircase community, giving rise to the term ‘vertical studentification’. A survey was conducted amongst university students to locate and quantify the floating population of students. Also, long-term residents and landlords were interviewed to assess the impact of students on the communities of apartment blocks. The study reveals that studentification does happen in a high-rise morphology but in a vertical and hidden way, making policy implications less straightforward.

a b s t r a c tThe paper deals with the timetabling problem of a mixed multiple-and single-tracked railway network. Out of all the solutions minimizing the maximum relative travel time, the one minimizing the sum of the relative travel times is selected. User preferences are taken into account in the optimization problems, that is, the desired departure times of travellers are used instead of artificially planned departure times. To find the global optimum of the optimization problem, an algorithm based on the bisection rule is used to provide sharp upper bounds of the objective function together with one trick that allows us to drastically reduce the number of binary variables to be evaluated by considering only those which really matter. These two strategies together permit the memory requirements and the computation time to be reduced, the latter exponentially with the number of trains (several orders of magnitude for existing networks), when compared with other methods. Several examples of applications are presented to illustrate the possibilities and excellences of the proposed method. The model is applied to the case of the existing Madrid-Sevilla high-speed line (double track), together with several extensions to Toledo, Valencia, Albacete, and Málaga, which are contemplated in the future plans of the high-speed train Spanish network. The results show that the computation time is reduced drastically, and that in some corridors single-tracked lines would suffice instead of double-tracked lines.

The proliferation of High Speed Trains (HSTs) in European countries has caused small, isolated cities within one hour's distance by HST to become partially integrated into metropolitan processes. These cities may be considered as a combination of small provincial centres and suburban metropolitan districts. Scientific literature suggests that subcentres in polycentric urban regions are becoming more numerous and diverse, that there are doubts whether HSTs are facilitating decentralization or concentration from/to metropolises, and that fewer HST effects are taking place in big cities than small ones, where HST contribution to accessibility amelioration is greater. The article discusses the types of urban residential processes according to temporal relations with HSTs (before and after HSTs) and spatial relations (HST station location). The conduct of household survey and review of building permits and mortgage valuations was done to analyse the urban process which these cities undergo with the development of HSTs. It was found that residence location with respect to the HST station varies with the type of inhabitant (local versus immigrant, tenant versus owner, etc.) and their relation to HSTs (commuter versus non commuter, etc.). It was also shown that the HST (alongside the presence of a university) helps isolated cities to acquire territorial roles of greater importance, by virtue of attracting intraprovincial immigration and familial investment, as well as immigrants and investments from other provinces.