The criteria currently employed for the design of railway infrastructure on ballasted track are based on the elements of the superstructure, traffic, and bearing capacity of the subgrade. In high-speed railway, the elements of the superstructure are relatively well defined because they are based on existing experience. The category of traffic is a variable that has an influence from the point of view of the number of axles, weight per axle, and speed; i.e., it is determined a priori, depending on the operating characteristics of the line in question. The third and last point refers to the quality of the subgrade that is based on the values of the California bearing ratio test. The quality of the subgrade has a considerable influence on the behavior of the track that manifests itself in the value the deformation and settlement takes, which is caused to the rail on the passage of traffic. This is attributable to the relationship between the vertical track stiffness and the quality of the subgrade. In turn, ...

The management of vehicle travel times has been shown to be fundamental to traffic network analysis. To collect travel time measurement, some methods focus solely on isolated links or highway segments, and where two measurement points, at the beginning and at the end of a section, are deemed sufficient to evaluate users' travel time. However, in many cases, transport studies involve networks in which the problem is more complex. This article takes advantage of the plate scanning technique to propose an algorithm that minimizes the required number of registering devices and their location in order to identify vehicles candidates to compute the travel times of a given set of routes (or subroutes). The merits of the proposed method are explained using simple examples and are illustrated by its application to the real network of Ciudad Real.

This paper considers the problem of modeling railway track substructure. The most commonly used methodology for designing the railway substructure cross section does not considerably differ from that proposed in the 1980s. For the bearing capacity of the subgrade, the currently used design methodology implicitly meets one objective: the stresses transmitted to the subgrade must be compatible with its bearing capacity. The bearing capacity depends on the qualities and thicknesses of the soils that compose the subgrade, from the formation layer to the lower layers. In addition, railway administrations have included additional recommendations based on their experience. During the last decade, finite-element models (FEM) have been shown to be a very useful tool for designing cross sections. These models are often very complex and require a very high computational time to be solved. To reduce this complexity and computational time while remaining faithful to the reality to be modeled, this paper proposes some recommendations to develop a parameterized numerical model in three dimensions within the elastic nonlinear range under the static load of a given railway section. To adequately reproduce the real behavior of materials (elastoplastic) and the contact surfaces between very different materials adequately, artifices to use the model in the elastic range are propsed. In addition, the goodness of this design is analyzed using multilayer numerical models. This model may be a very useful tool for analyzing the behavior of different types of railway cross sections.

In recent years, different techniques to address the problem of observability in traffic networks have been proposed in multiple research projects, being the technique based on the installation of automatic vehicle identification sensors (AVI), one of the most successful in terms of theoretical results, but complex in terms of its practical application to real studies. Indeed, a very limited number of studies consider the possibility of installing a series of non-definitive plate scanning sensors in the elements of a network, which allow technicians to obtain a better conclusions when they deal with traffic network analysis such as urbans mobility plans that involve the estimation of traffic flows for different scenarios. With these antecedents, the contributions of this paper are (1) an architecture to deploy low-cost sensors network able to be temporarily installed on the city streets as an alternative of rubber hoses commonly used in the elaboration of urban mobility plans; (2) a design of the low-cost, low energy sensor itself, and (3) a sensor location model able to establish the best set of links of a network given both the study objectives and of the sensor needs of installation. A case of study with the installation of as set of proposed devices is presented, to demonstrate its viability.

The traffic flow on road networks is dynamic in nature. Hence, a model for dynamic traffic flow estimation should be a very useful tool for administrations to make decisions aimed at better management of traffic. In fact, these decisions may in turn improve people’s quality of life and help to implement good sustainable policies to reduce the external transportation costs (congestion, accidents, travel time, etc.). Therefore, this paper deals with the problem of estimating dynamic traffic flows in road networks by proposing a model which is continuous in the time variable and that assumes the first-in-first-out (FIFO) hypothesis. In addition, the data used as model inputs come from Automatic Number of Plate Recognition (ANPR) sensors. This powerful data permits not only to directly reconstruct the route followed by each registered vehicle but also to evaluate its travel time, which in turn is also used for the flow estimation. In addition, the fundamental variable of the model is the route flow, which is a great advantage since the rest of the flows can be obtained using the conservation laws. A synthetic network is used to illustrate the proposed method, and then it is applied to the well-known Nguyen-Dupuis and Eastern Massachusetts networks to prove its usefulness and feasibility. The results on all the tested networks are very positive and the estimated flows reproduce the simulated real flows fairly well.