Page 8 - Research and innovation un materials applied to railways

development of new materials that modify the coefficient of friction, applied on the rail
tracks. Finally, the development of new “intelligent” materials whose rigidity and damping
properties vary in accordance with the needs at any point during the service, or that
integrate new functions, such as the sleepers or bearing plates that are capable of
generating energy from the vibrations formed when the vehicle passes over them (energy
harvesting), are lines of development with great potential.

IV. FACILITIES

The catenary, together with other facilities, track and safety elements, are fields in which
innovation and new materials play a fundamental role. The need to increase service life
under extreme conditions of heat and humidity, the wear caused by wind suspended
particles and actions derived from the wind, together with the reduction of costs
associated with facilities and maintenance, are factors which justify the application of new
materials in rail system structures and facilities.

Facilities sometimes need to be constructed in places with difficult access. Furthermore,
the complexity of these types of operations can increase considerably due to the
unavailability of equipment in the area needed to facilitate the installation. In summary,
the overhead line, poles, cantilevers and registration arms are, at times, parts which are
complex to transport to the site of installation both due to weight and dimensions.

It is possible to resort to alternative materials that, as well as delivering the necessary
benefits, are lighter in weight and facilitate transportation, approach and assembly.
Polymer-matrix composite materials profiles offer excellent characteristics in terms of
lightness and resistance in extreme environmental conditions of hot and cold, humidity or
solar radiation. The manufacturing of these profiles through pultrusion techniques is a
highly competitive solution, with the processes of manufacture and paint automation
being the object of a number of R&D projects. There are also developments in registration
arms in polymer-matrix composite materials and these materials are also supporting
improvements in the life cycle of insulators. Other components, such as poles, could also
be improved through the use of these materials.

The phenomena related to the contact between the catenary and the pantograph has
always been a focus of research and development, due to the problems of mechanical wear
and the requirements of electrical properties. New materials can contribute towards
increasing service life under adverse meteorological conditions. In this way, the objective
of tribological studies of materials has been performance improvement, minimizing
energy loss and wear. Traditionally these studies have been limited to electrolytic copper
(ETP), with alloys such as Cr, Zr, Ag y Mg or graphite.

These studies can be extended to include variables such as the degree of humidity or the
salinity or the parameters of thermomechanical copper treatments. Furthermore, as
alternatives to electrolytic copper, new poly micro-alloys have been developed with
higher temperatures of recrystallisation and improved mechanical properties, which
provide greater resistance to wear and low temperature creep.

Less wear decreases maintenance costs and a higher annealing temperature increases the
capacity of the contact wire to bear peaks of intensity. The contact between the catenary

Position Paper: Research and innovation in materials applied to railways 7