Rational structure is of box construction, adequately designed and reinforced by stiffening ribs, to take care of all types of loadings. This is connected by cross beams. The unbraced legs are hinged near the leg beam attachment. The complete structure is mounted on four wheel base, each having two double rimmed steel wheels provided with flexible bushing to take care of any misalignment. The top beam is firmly fixed on heavily fabricated steel bracket. The crab carriage is in steel section. It is comprised of special crane duty motor, connected to heavy duty speed reducers and are coupled up to a grooved steel drum. Electromagnetic brakes / hydro-thruster brakes are used to control the smooth lifting of weight. The block is equipped with a forged steel forked revolving hook.
Wire Rope is of 6 x 37 construction. Access ladder leading, to inspection walkway, which runs along one beam and is made of walking surface with railing and foot-guard. Electric operations are controlled with push button control unit, independent from the position of Winch Trolley and sliding in loop through cable carriers. Limit switches for cross to ensure accident free operations.