The railway transport network is currently in a quite big expansion. Therefore, railway tracks are modernized and the attention is given also on the technical state of rail vehicles, which operate on them. However, it may happen that the wheel surface is damaged. One of the most common reasons of wheel damage is too much braking, which results to the wheel-flat formation. This article is focused on the evaluation of the influence of a rail vehicle running on the railway track, which a wheel is damaged by the wheel-flat. Investigation of these negative effects was performed by means of simulation computations. As evaluating parameters, values of the wheel force in the contact of the rail and wheel with a flat where observed.