Attractive rail freight transport services require the availability of an efficient infrastructure both on the lines and in the hubs. The quality-oriented and economical dimensioning of track groups in rail freight stations is therefore an essential task of strategic infrastructure planning. The main goal is to determine the required number of tracks and the necessary track characteristics. This paper describes an optimisation model for dimensioning rail freight stations by explicitly considering the track occupancy in a track group and minimising the number of trains waiting in front of the track group. Waiting probabilities can be derived from this, which represent an established decision-making parameter for the dimensioning of track groups.