Abstract: A twin post lift has a master and slave cylinder system in which the maser and slave cylinders each drive a lifting carriage, and each of the lifting carriages is mounted within, and is restricted to longitudinal travel within, an upright member. In the event that there is a loss of pressure in the hydraulic system under load, it is important that the lift be prevented from descending unexpectedly, or uncontrolledly. The upright can be manufactured in the form of a roll formed channel section. The legs of the channel section are formed to define guides for guide followers mounted on the lifting carriage, thereby restraining the travel of the lifting carriages to travel in the vertical direction. The lifting carriage has a rack formed on its back face. The rack is nested within the upright member and is not visible in use. The back of the channel is formed with an outwardly protruding step to accommodate the rack.