On the other hand, the analysis of scale, scope and industry structure involving relatively
simple transport networks technically described in detail, has generated important
conclusions. For synthesis, we have been able to show the process through which cost
advantages arising from a network expansion (new nodes served) are realized. In essence,
fleet capacity can be better used by means of variations in the route structure when new
flows are incorporated to production after this type of network expansion. From a
microeconomic viewpoint, this translates into economies of scope, which have been shown
to exist even under constant returns to scale (in this case, the absence of fixed costs). This
provides a new conceptual framework that might help understanding the observed behavior
in some transport industries, which is a problem that, so far, has been analyzed as a scale
property, an inadequate approach in our view.