Abstract: A steering system for a gantry-type crane includes a hydraulic cylinder coupled to each wheel and operable to turn the same through at least a right angle. A hydraulic control system includes a first control valve having a two-wheel steering mode for connecting a first pair of cylinders to a pressure source and in a series relation with each other for two-wheel steering and having a four-wheel mold for connecting the first pair of cylinders in a parallel relation with each other for four wheel steering. A second control valve means has a two-wheel mode for isolating a second pair of cylinders from the pressure source and a four-wheel steering mold for connecting the second pair of cylinders to a pressure source. The first and second control valve means are selectively operable for sequentially moving each of the pairs of cylinders between their first and second steering modes.