A steerable track system usable with a vehicle that has a chassis, an axle frame extending laterally outwardly from the chassis and having an attachment portion at an end thereof to which the steerable track system is connectable, and a driven shaft extending laterally outwardly from the chassis suitable for driving the steerable track system. The steerable track system has a frame having a cavity defined therein and being operatively connectable to the axle frame so as to be pivotable about a steering axis for steering the track system, and a gear train with components disposed in the cavity. The gear train transmits driving forces from the driven shaft to a driven wheel assembly of a plurality of track-supporting wheel assemblies. An endless track extends around the track-supporting wheel assemblies and is drivable by the driven wheel assembly.