A steerable track system (40, 1040, 1640, 2040) for use with a vehicle having 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 (40, 1040, 1640, 2040) is connectable, and a driven shaft extending laterally outwardly from the chassis suitable for driving the steerable track system (40, 1040, 1640, 2040), the steerable track system (40, 1040, 1640, 2040) comprising: • a frame having a cavity extending longitudinally therein and being operatively connectable to the axle frame so as to be pivotable about a steering axis for steering the track system (40, 1040, 1640, 2040); • a gear train, the gear train including a plurality of gears, the plurality of gears including: o an input gear mounted on an input shaft rotatable about an input gear axis, and o an output gear longitudinally spaced apart from said input gear, the output gear being mounted on an output shaft longitudinally spaced apart from said input shaft, the output shaft being rotatable about an output gear axis, the input and output gears (210, 220) being disposed within the cavity, the input gear being operatively connected to the output gear to drive the output gear, and the input shaft being operatively connectable to the driven shaft of the vehicle; • a plurality of track-supporting wheel assemblies (160a, 160b) rotatably mounted to the frame and including a driven wheel assembly, the driven wheel assembly being operatively connected to the output shaft; and • an endless track extending around the plurality of track-supporting wheel assemblies (160a, 160b) and being drivable by the driven wheel assembly. • a frame having a cavity extending longitudinally therein and being operatively connectable to the axle frame so as to be pivotable about a steering axis for steering the track system (40, 1040, 1640, 2040); • a gear train, the gear train including a plurality of gears, the plurality of gears including: o an input gear mounted on an input shaft rotatable about an input gear axis, and o an output gear longitudinally spaced apart from said input gear, the output gear being mounted on an output shaft longitudinally spaced apart from said input shaft, the output shaft being rotatable about an output gear axis, the input and output gears (210, 220) being disposed within the cavity, the input gear being operatively connected to the output gear to drive the output gear, and the input shaft being operatively connectable to the driven shaft of the vehicle; o an input gear mounted on an input shaft rotatable about an input gear axis, and o an output gear longitudinally spaced apart from said input gear, the output gear being mounted on an output shaft longitudinally spaced apart from said input shaft, the output shaft being rotatable about an output gear axis, • a plurality of track-supporting wheel assemblies (160a, 160b) rotatably mounted to the frame and including a driven wheel assembly, the driven wheel assembly being operatively connected to the output shaft; and • an endless track extending around the plurality of track-supporting wheel assemblies (160a, 160b) and being drivable by the driven wheel assembly.