Safety and security are among the major basic needs for the public in daily life and transportation plays a crucial role in satisfying this need. According to the World Health Organization (WHO) data, estimates of 1.2 million people worldwide died as a result of road traffic injuries in 2013 and it is estimated that road traffic injuries will be the 6th leading cause of death by 2030. Among the various types of road traffic injuries, accidents between trains and road vehicles are the deadliest and are associated with high cost of accidents. As Railway transportation continues to be an important piece to the overall national transportation puzzle in Ethiopia and as congestion continues to increase on the nation’s roadways, commuters continue to flock to public transit as an alternative transportation mode. In Addis Ababa Light Rail Transit, there are over 20 level crossings, this represent a significant safety hazard to both road and rail users. In this paper, we used safety demonstration by complete system analysis to carry out safety demonstration for level crossing at Addis Ababa Light Rail Transit, and Failure mode effect analysis was used for identifying the potential hazards associated with the system and their root causes. Hazards associated with Addis Ababa Light Rail Transit level crossing are identified and classified, and results showed that 41% of the hazards are caused by Human errors, technical problems has 32%, non-compliance with standard operating procedures takes 18% and 9% are caused by other factors. Our Failure mode effect analysis result shows that safe redesign of the level crossing, management and operation of level crossings can reduce risks, and frequent orientation of road vehicle users to always give attention to traffic signal in level crossing can reduce the number of fatal and serious incidents and collisions.

For predictive maintenance purpose, wheel and rail wear evolution models have been developed based on wheel rail contact force calculations. These models are known to assume the wheel rotating on a rigid rail. However recent developments have shown that the flexibility of the track plays an important role in wear evolution. On the other hand, vertical track stiffness variation along the track is known to exist and to affect the track flexibility. The present research work investigates the influence of non-uniform track modulus on the wheel rail contact forces using elasto-plastic explicit dynamic Finite Elements (FE). The FE model is composed of a quarter car model running on a rail supported by three cross-ties. The modulus of elasticity of the cross-ties is calibrated to produce the total track modulus of the railroad track infrastructure. Non-uniformity of the track is modeled by assigning distinct elasticity moduli to the cross-ties. The instantaneous contact physical parameters are extracted from FE models repetitively for various cross-tie modulus ratios. The results show that increase in cross-tie modulus variation results in increased fluctuation amplitudes of wheel-rail contact parameters such as force, stress and contact area. This effect leads to changes of the rate of material removal on the wheels and rails. This research work intends to incorporate the spatial variation of the railroad track stiffness into rail vehicle wheel and track wear prediction models.

The aim of this analysis was to model the pantograph - catenary system at static equilibrium and provide analytical solutions by computing the natural frequencies of the system, mode functions, equivalent stiffness of the catenary system and the deflections of the catenary wire as a function of position, time and tensioning force. Furthermore, dynamic analysis was conducted analytically and the results of the dynamic performance were obtained. It was shown that the dynamic response of the catenary system is dependent on the design parameters in which tensioning force is included. It was also shown that low tensioning forces result in high risk of contact loss and increased wave propagation in the catenary wire while high tensioning forces result in increased static stresses in the catenary system. The results in this article can be used to select optimum tensioning forces and design parameters for desired pantograph-catenary dynamic performance.