In the 1920s, quarries and hard-rock mines were expanding their use of shovels to load haulage vehicles with larger quantities of material than ever before. The only shovels heavy and robust enough for tough quarry work were the old-faithful steam railroad shovels, many of which had found their way into large quarrying operations. Although some had latterly been converted to crawlers, freeing them from restrictive railroad tracks, their working capabilities were still severely hampered by long steam boilers at the rear, and boom and dipper assembly with swing limited to about 180 degrees. Shovels with 360-degree swing were available, but these were either small construction-sized units or long-boomed gangly stripping shovels not robust enough for hard digging. Clearly there was a need for a machine that combined the railroad shovel's robustness with the stripping shovel's full-swing capability.
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