The wheel flat is a phenomenon in which a part of the wheel tread is cut away to become a flat surface. It is known that wheel flats increase the noise during traveling and that the high impact acceleration generated by flats has a major impact on vehicle and track damage, deterioration, and life. Therefore, it is important to analyze the generated impact acceleration with high accuracy. In this study, a rolling contact analysis was performed using a bogie model with a flat, and the impact acceleration generated and the distribution of the normal contact force on the contact surface was evaluated. As a result, it was found that the impact acceleration and normal contact force due to the flat affect not only the wheel with the flat but also the opposite wheel through the axle. It was also found that the stress distribution on the contact surface was asymmetric between the wheel and the rail due to the rotation of the wheel and that the rail generated higher stress.