The Mechanical Handling and Storing of Material

42o THE MECHANICAL HANDLING OF MATERIAL trestle and bins. The plant has a capacity for unloading a 10,000-ton boat m fifteen hours. Most of the latest machines are entirely electrically driven; some, however, are driven by steam or hydraulic power. Fig. 592 shows unloaders of the Pennsylvania Railroad Co., which grab 1/ tons at a time. Fig. 593 shows the 10-ton grab of a similar installation of the Corrigan McKimey Co. A 15-ton capacity Hulett unloader at the plant of the Pittsburg and Conneaut Dock Co., Ashtabula, Ohio, is shown in Fig. 594.