Ballastless Track Systems Road to Rail Synergies for Better Transport Infrastructure
Last modified: 2017-02-28
Railway engineers built capable road infrastructure at the beginning of the last century. Today road pavement technologies and respective long-term experiences still foster significant developments in rail infrastructure, especially towards durable tracks meeting low maintenance and high availability requirements for high speed as well as for urban rail. Properly designed and constructed concrete pavements handle high traffic loads like trucks, aircraft and trains. They provide durable and accurate rail alignment and consistent track stiffness, which is essential for high-speed rails. German road pavement design follows the jointed plain concrete pavement (JPCP) concept beside the usage of asphalt pavements. The absence of steel reinforcement would be attractive to rail applications with respect to electric isolation and electromagnetic compatibility requirements. But, the cracking behavior must be controlled safely by proper crack guidance and joint design as well as the risk of permanent deformation of asphalt pavements. Studies of dynamic vehicle track interaction using Multi-Body-Simulation tools show the importance of track stiffness quality beside track geometry leading to the request of unjointed, continuous rail support, which is given by e.g. by asphalt or continuously reinforced concrete pavements (CRCP). Also tracks made by prefabricated slabs offer longitudinal consistency in case the coupling joints transfer horizontal and vertical forces on appropriate level. Ballastless track systems require appropriate support conditions dependent on the type of sub-structure (bridge, tunnel, earthworks), especially along transitions between different sub-structures. Economic track design needs the help of numerical tools (Finite Element Models FEM) to achieve sufficient load distribution by the track structure to adjust the stress level on the supporting structure with respect to plastic deformations (settlements) during service life. The paper gives on overview of the actual research on ballastless track technology as well as on the actual progress of European standardization.
ballastless track; vehicle-track interaction; concrete pavement; asphalt pavement; road-rail synergies