There are significant number of cars uncoupling that leads to downtime, safety reduction, and time-consuming repairs. It happens due to the fault of running parts. The main unit of a freight car designed for reduction of vibration and levels of the dynamic vertical and horizontal forces is a spring suspension with friction wedge shock absorbers. The durability of details is a priority in determining the average runtime of the car truck. In this case, one of the urgent problem is to improve performance of shock absorbers, thus increasing the overhaul life of freight cars. Roundhouse servicing data include measurements of technical state parameters of 25,000 friction wedges. Statistical analysis of primary operational data of friction wedge shock absorbers is presented in the paper. The analysis reveals the dependencies between the total wear of angled and side walls, total average residual hardness and runtime between planned maintenance. A 3D visualization model is proposed for primary operational data visualization for further exploratory analysis.