Issue link: https://read.dmtmag.com/i/1515056
I DA U N I V E R S A L J a n u a r y - Fe b r u a r y 2 0 2 4 41 Early excavators were partial-swing steam shovels mounted on flanged wheels. Starting with the invention of William S. Otis in 1835, the first successful excavating machines were partial-swing steam shovels mounted on flanged wheels for use on railroad track. The boiler and mechanical works were on a fixed platform, and the dipper swung roughly 90 degrees left or right. Large rail-mounted shovels continued to be used into the early 1930s, until they were rendered obsolete by advances in mounting and full-revolving technologies. One aspect of that obsolescence was that the machine was confined to the rails, which were usually temporary tracks laid to access the work and shifted as needed, with all the atten- dant costs. Crawlers and steel wheels enabled free travel, with the only limitations being ground conditions, slope, and clearances. Yet no full-revolving machine large enough for the heaviest digging and loading applica- tions existed until Bucyrus-Erie introduced its 120-B 4-yard electric shovel in 1925; the 120-B dispensed with costs and limitations not only of rail-mounted operation and partial swing, but also of steam operation. But not all owners of the big rail-mounted shovels bought into this new technology. For all its advances, it still required varying invest- ments in generating or purchasing electricity and transferring it to the shovel. Some owners had their railroad shovels converted to mobile use through various combinations of crawlers and/or steel wheels. It's not known whether the owners instigated this idea, or if the manufacturers did to protect market share. The Historical Construction Equip- ment Association (HCEA) is a 501(c )3 nonprofit organization dedicated to preserving the history of the construc- tion, dredging and surface mining equipment industries. ● www.constructionequipment.com 1/24 Steam Shovels Move from the Rails Osgood shovel Railroad tracks? We don't need no stinking railroad tracks! An unidentified Osgood shovel models an all-wheel conversion in this circa 1923 image. Note the cleats on the front wheels for traction. (Osgood Co., Marion Power Shovel Co. collection, HCEA) Marion-Osgood 73 A Marion-Osgood 73 railroad shovel gets some attention at the plant in Marion, Ohio, before shipment to contractor Henry A. Whitley of San Francisco. Note the chain operation of the dipper and shipper shaft; wire rope technology had not yet evolved to take the gaff, to use a phrase of the time, of this application. Osgood 73 In June 1924, another 73 shovel sports a set of four oscillating crawler assemblies instead of wheels. Note the drive shaft to the crawlers, and that the front is still chain-driven.