Abstract: A track system includes a track 1 and one or more carriages 10 having bearing wheels engaged with the track such that the carriages can travel along the track. Each carriage has a single bearing 12 engaged with the inner side of the track and a pair of bearing wheels 13, 14 engaged with an opposite side of the track. The width of the track between the two sides varies such as to maintain a tolerance better than 0.05 mm between the bearing wheels and the respective sides of the track. The load capacity of the carriage can be increased and centred by making the single bearing 12 larger than the other two bearing wheels 13 and 14. The track 1 may be machined in one piece, optionally with an integral base plate. In another embodiment the track has spaced inner and outer sections with a rack engaged by a drive pinion mounted on the carriage between the two sections.