The key element of the Slab Track Austria or ÖBB–PORR system is an elastically supported 5.2m x 2.4m precast slab, built on a solid or low-subsidence base structure such as, for example, a tunnel, bridge, a hydraulically bonded base layer or a (heavy) mass spring system.
The bottom of the un-tensioned reinforced precast slab as well as the tapered openings are covered with an elastic layer which provides the system with double-layered elasticity, reduction in the vibrations or structural-borne noise, and decoupling from its structural supports. The integrated elastic layer enables a quick and easy repair should that become necessary. A joint width of a minimum of 40mm separates two panels to compensate for any deformations caused by environmental influences such as creeping, shrinking and temperature-caused movements. The joint also provides space for drainage or cable-crossing components.
The slabs are grouted and fixed on a thin base layer constructed from self-compacting concrete (SCC). By using this type of concrete, homogeneous setting is achieved and it is not necessary to vibrate the concrete. Thus, disturbances of the final track alignment are reduced to a minimum and highly precise alignment of the track achieved. As the concrete hardens the tapered openings work as anchors, and vertically and horizontally lock the panel in place. As a rule the system height from the top of the substructure to the upper edge of the track is ≥ 43cm.
Unlike sleeper systems, Slab Track Austria panels can provide openings in the track, for example for revision and bearing shafts wherever needed.
The Slab Track Austria system has been tested and proven in operation with Vossloh and Schwihag fastenings, but it can also accommodate other fastening products (e.g. Pandrol).