The invention relates to a modular crawler-track unit for a forest machine, which crawler-track unit (14) includes - a crawler-track frame (16), a sleeve axle (77), for supporting the crawler-track frame in the forest machine, a crawler mat (18) arranged in a circulation, at least one drive wheel (20) mounted in bearings in the said crawler-track frame (16), at least one idler wheel (23) mounted in bearings in the said crawler-track frame (16), support means (25), which are arranged to conform according to the shape of the surface of the ground, in order to distribute the surface pressure of the crawler-track unit (14) evenly, and a drive shaft (60) mounted in bearings in the said crawler-track frame (16). The crawler-track unit (14) further includes - a shaft (80) mounted in bearings on the crawler-track frame (16) for pivoting the said drive wheel (20) to the crawler-track frame (16) at a distance from the drive shaft (60), and power-transmission means (41) fitted between the said shaft (80) and the drive shaft (60) for transmitting power from the drive shaft (60) to the drive wheel (20). The invention also relates to a corresponding forest machine.
