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As rails are vital parts of a track system, it is essential to ensure their safe and reliable operation. The present verification approaches and limit values regarding the permissible additional stresses of the rail under compression and tension considering track-bridge-interaction (TBI) were developed in the 1980s. However, with the rapid development of the railway industry and the increasing of train speeds, rail infrastructures are subjected to ever more frequent, greater loads and more complicated loading conditions, especially in the area of bridges. Moreover, the manufacturing technologies of railway components have been further developed. Taking all the aforementioned variations into account, the current verification approaches and limit values do not apply properly today and shall be updated. For this purpose, new investigations are carried out in this dissertation. As major parts of this cumulative dissertation, the published investigations are divided into three main blocks. The first block is the state of the art. In this block, a detailed background knowledge and a state of the art description of the permissible additional stresses in railway tracks due to TBI are given. Furthermore, the motivation for the studies within the scope of this dissertation is addressed. The second block deals with the rail resistance under compressive forces in ballastless track systems. Accordingly, numerical investigations on the behaviour of rails in ballastless track systems under compressive axial forces in the vicinity of bridge joints were performed. Experimental tests were also carried out on two 8.17 m long rails fixed with BSPFF-B-1 and SBS300-1 fasteners on the ÖBB-Porr slab track system. It was found that the rail resistance under longitudinal compressive loads can be largely increased. The third block focuses on the rail resistance under tension. First, extensive experiments were conducted on rail behaviour for up to five million cyclic loads in both vertical and

The movement characteristics of a rolling-damper isolation system were analyzed to obtain a numerical analysis approach. Computer programs were compiled to analyze the influence of factors such as rolling friction coefficients and damping constants on the earthquake response of the isolation system. The rolling friction and the damper can efficiently decrease the relative displacement of the isolation system, and can considerably increase the acceleration of the isolation system. However, they cannot regularly affect the residual displacement of the isolation system. Therefore, when subjected to design earthquakes, it is desired to obtain a reasonable combination of damper and rolling friction that can decrease the relative displacement of the isolation system to the best while keep the acceleration of the isolation system in an allowable range. This paper provides suggestions on the optimized combination of damper and rolling friction for seismic design of isolation systems.