Construction, maintenance and upgrading of tracks: the Austrian way
1 August 2013 • Author(s): Michael Walter, Bernhard Knoll and Jürgen Stern, Business Unit Integrated Railroad Line Management, ÖBB-Infrastruktur AG
The liberalisation of European railways, particularly the free network access of passenger and freight traffic, have a basic influence on the construction of new lines and the maintenance and upgrading of tracks of ÖBBInfrastruktur AG. This article outlines the essential characteristics of track systems including track substructure.
Line layout and cross sections
Operating trains on a line that allows high speeds for passenger trains and low speeds for freight trains requires careful consideration about track alignment design. The maximum allowable values of cant deficiency (Imax = 130mm) and a max. cant excess (Emax = 110mm) enables expectable rail wear and reduced maintenance costs. A maximum gradient of 12.5‰ guarantees a load of 1,000 tonnes per freight train. A minimum radius of 3,000m enables a comfortable train speed of 200km/h, but 250km/h for trains with low axle loads is also possible.
The invention of the ‘Viennese Curve’ – a transition curve calculated for the centre of gravity of a vehicle – reduces lateral track forces and rail wear. In addition, this transition curve guarantees a full compensation of the rate of change of the lateral acceleration at the points of discontinuity – as a result, new and better passenger comfort will occur.