چكيده به لاتين
Train's Safe running is directly related to its subsystems, such as Railway Track and structures including bridges and tunnels, railway vehicles and its operation characteristics such as speed. Therefore, in order to ensure the safe running, it is necessary to compile thresholds in each subsystem. Particulary in railway track subsystem, geometric parameters and track quality, speed proportions with track quality and its defects, tolerance of track parameters and the railway vehicle are specificly important. One of the factors that endangers train's safe running is Derailment. Derailment is considerd one of the most common railway accidents in the world that can be affected by the quality of the railway Track. The study of this phenomenon requires a comprehensive perception of train's dynamical behavior and the wheel-rail contact mechanism.
The undesirable track quality condition will cause the derailment by increasing the lateral forces on the wheel. This situation is more critical when the train is runnig on curves, because in the curve due to the track geometry and the centrifugal force, the amount of lateral force acting on the outside wheel, increases. Therefore, if the track quality condition in the curve is undesirable, the probability of train derailment will increase.
In this thesis, the mechanism of occurrence of train derailment along with the factors and conditions that causes the incident are introduced and analyzed. The assessment of train's safe running was done by assessing the derailment reliability on curves, taking into account the impact of three geometric parameters including Cant, twist and Gauge. Then examining the impact of these parameters in the tolerances associated with each of them at the qualitative and a variety of regulations were analyzed and evaluated. Finally, by analyzing the sensitivity of the parameters, it was determined that the effect of each parameters studied in the curves is on the likelihood of occurrence of derailment. According to the results, an index for assessing the safe running on the curves was proposed based on the statistical data of the influencing geometric parameter which was Cant. Finally, using the evaluation method and proposed empirical model, the safe speed for the evaluated geometry condition is estimated according to the track quality and operation classes.
Keywords: Safety; Reliability; Track Geometry Parameters; Train derailment on Curve; Track quality.
