Continuous monitoring with advanced equipment and innovative scientific techniques is essential for timely and perfect maintenance. The interaction and dynamic force between wheel and rail is one of the most widely monitored issues. In this paper's case study of ballasted railway tracks in Iran, a set consisting of two separate strain gauge arrays and three different positions for installing accelerometers were designed according to the conditions. After installation, the system was calibrated with a predetermined passing axle load. The dependency of the arrays' and the equipment's installation location with the velocity of the passing axle load was examined as part of the field study after repeated investigation and comparisons of the setups' results. In order to gather data with the least error and the highest level of accuracy, it was decided on the more appropriate array with less dependence and a better installation position.