The present invention is related to a track unit for a vehicle, such as an agricultural harvesting combine. The track unit according to a first embodiment of the invention comprises one or more bogies arranged between front and rear guide wheels. The bogies are provided with wheel pairs that are rotatably arranged about a longitudinal axis of the bogie itself, and are thereby capable of adapting individually to transversal oscillations caused by the terrain. Preferably, the bogies are furthermore equipped to adapt to longitudinal oscillations as well, by the longitudinal portion of the bogie being rotatable about a transversal axis. According to a second embodiment, the track unit of the invention is equipped with a cutter, non-rotatably mounted on one or both outer faces of the rear guide wheel, in a position where said wheel is in direct contact with the track, the cutter being configured to cut crop material that is transported upwards between the rear guide wheel and the track when the track unit moves forward.