Abstract: A portable electric sign display unit comprises a wheeled trailer having a main frame on which is mounted a motor-generator unit and a structure for holding a warning sign or the like in an elevated position. The sign carrying structure is collapsible into a position in which a central portion of the sign panel forms a roof over the motor-generator unit and two hinged side panels form the sides of the cover for the unit. The sign is erected by operation of a winch which first rotates the sign panel toward its vertical position and then raises the structure a further distance to the fully elevated position. The side panels are locked into position in the same plane as the central portion and electric lights forming the display are mounted on all three portions.