Measuring the Evolution of the Flexibility of a Railway Network

Eugenio Roanes-Lozano (1), Luis M. Laita (2), 
Eugenio Roanes-Macias (1), Jose Luis Ruiz (3), 
Carlos Roncero (4)

(1) Departamento de Algebra, 
    Universidad Complutense de Madrid
(2) Departamento de Inteligencia Artificial, 
    Universidad Politecnica de Madrid
(3) Escuela Superior de Ingenieros Industriales, 
    Universidad de Sevilla
(4) Escuela de Ingenierias Industriales, 
    Universidad de Extremadura

The goal of our work is to design and develop a piece of software that can
objectively evaluate the evolution of the flexibility of a railway network.  We
have focused on the topology of the network considered as a graph (ignoring
quality indicators).  We have considered two indicators as the most accurate in
this sense: the number of cycles that provide an alternative to reach a station
and the number of stations of intermediate degree.  We have chosen to implement
an ``ad hoc'' extension of Maple's networks package.  It has been applied to
study different steps of the evolution of the Spanish national broad gauge
network (1956-2006) as illustration.

This work is partially supported by the research project MTM2004-03175
(Ministerio de Educacion y Ciencia, Spain.)