The mobile television camera trolley has a telescopic frame with two main members. The lower end of the lower member slides along a horizontal bar and the upper member carries the camera platform and the cameraman's seat. A toothed pinion runs on a shaft on the upper member and carries a chain which controls the vertical displacement of the camera and seat. The chain also rolls on the toothed wheel on the upper member and on the inner teeth of a wheel mounted on the lower member. A second chain is fixed to the axis of the upper toothed wheel and rolls around part of the circumference of the lower toothed wheel.