This paper describes strength analysis for the flat wagon. The analysis is conducted by experiment methods using testing the flat wagon prototype with static loads such as vertical load, compression load, twist load, jacking load, and combination of them.The result of test such as stress and camber is analyzed against the design requirement and national regulation to assess the reliability of the flat wagon structure.The result of test shows that the critical area under compression load and vertical load occurs at the “end center sill” and the “central center sill”, respectively. Maximum stress of the flat wagons structure is 271.32 N/mm2 equal to 76.4% of yield stress of base material. It occurs at combination of vertical and compression loads. It indicates that the flat wagon structure is feasible to be operated with maximum capacity of 40 tons.