Abstract: A triplex trim mower (100) including a vehicle (102) having two front drive wheels (104) and one rear steerable wheel (106). Mounted generally forward of the front wheels (104) are two reel-type cutting units (108a) laterally offset about the longitudinal axis (110) of the vehicle (102). Mounted between the front and rear wheels and substantially centered between the forward cutting units (108a) is a rear reel-type cutting unit (108b). A lateral support frame (137) is incorporated into the main frame of traction vehicle (102). The cutting units (108) are supported by a lateral carrier frame (144) which is slidably engaged to lateral support frame (137) such that carrier frame (144) can move laterally relative to support frame (137). A hydraulic cylinder (158) permits carrier frame (144) to be laterally displaced under operator command. Second and third hydraulic cylinders (131) permit cutting units (108) to be moved between a transport position and an operating position.