An apparatus includes a first element for identifying planned applications of tractive effort and braking effort for a railway vehicle while traversing a track segment. The apparatus includes a second element for determining a slack condition of the railway vehicle at one or more locations on the track segment in advance of the railway vehicle traversing the track segment based on the planned applications of tractive effort and braking effort. The apparatus includes a third element for redetermining the slack condition at the one or more locations based on at least one deviation from the planned applications of tractive effort and braking effort.