This paper is focused on various experimental stages for engineering, science, and approval processes, including: (a) details of tested objects such as transport-overrun platforms with a coupling ball for vehicle connections and their installation in the T-slot testing area, (b) fatigue cracks and zones across different sections of the examined object types, (c) results of mechanical tests on specimens for the approval process. It highlights differences in platform mounting caused by supports and screws, as well as the vehicle axle, with transport belts used for coverage during operation. Cracks are illustrated in macro-photographs of the platform stringers and subframes, which are made of aluminium alloy and structural steel grades. Fracture regions are depicted in approved coupling balls after durability tests, illustrating characteristic features caused by applied cyclic force components in two directions: vertical and horizontal. The results of tests on specimens include the response of the 6005 T6 weld aluminium alloy under tensile force, and follow the Wöhler curve of S700MC high-strength steel with its welded joint, at SEM observations for fatigue region features. All results cover the efforts made for the Polish automotive industry for type approval and product sales within and outside the European Union.