HISTORY OF STEAM SHOVELS

PART 7

enry M Barnhart’s experience as a steam shovel operator in the early 1880s led him to design his own machine. He was continually annoyed by breakages and delays caused by inadequate designs unable to withstand stresses brought on by heavy excavation. In those days, the only shovels known were the “railroad type” where the shovel’s boiler and draw works were mounted on a railway car and the boom and shovel assembly swung a little more than 180 degrees at one end. So, although Barnhart’s design was a railroad type, it included the following improvements: i) The machine was mounted on standard gauge railway trucks rather than broad gauge wheels as other makes, thus allowing easy movement between jobs. ii) Motions were operated by friction clutches. iii) The swing turntable was mounted at the bottom of the vertical mast rather than the usual position at the top of the mast at roof level. This resulted in a