By Susanna McLeod
Special to Ontario Construction News
Working in air conditioned comfort, the excavator operator shifts soil, rocks, and other materials using joysticks and pedals to dig and move. The windowed cab has communications, perhaps Bluetooth, and screens, providing instant information. Today’s machines may have been mere science fiction when the first excavator was patented in the mid-1800s—an Otis steam shovel.
A partner with a Philadelphia, PA contracting firm, civil engineer William Smith Otis developed a digging machine for railway and mining use. According to specifications of US Patent #1089 issued on February 24, 1839, Otis’ excavator was steam-powered by a coal-fuelled boiler.
According to the patent, the machine was “stationed upon a movable carriage, or car, and is situated on a temporary railway, and is intended to be so constructed that the load of earth taken off by the scraper may be raised by (the crane), while the turning of the crane also to the point where the load is to be dumped, whether into cars or boxes on the road, or elsewhere, is controlled and regulated with great precision.”
Regrettably, 26-year-old Otis died of typhoid shortly after receiving the patent and did not enjoy acclaim for his work. (His cousin, Elisha Graves Otis, was founder of the Otis Elevator Company.)
The modern excavator is generally a one-operator machine, able to perform most functions to dig, turn, carry, and relocate. However, the massive steam shovel required a team of workers. Along with a supervisor, the excavator crew included the engineman and the cranesman, one fireman, and four or more labourers. One purpose for labourers was to construct portable train tracks on which the steam shovel rested.
The engineman directed “the movements for raising and lowering the dipper, swinging it into position for unloading, and moving the machine forward and backward,” said E.A. Hermann in Steam Shovels and Steam Shovel Work (1894). “The cranesman regulates the depth of the cut made by the dipper, releases it from the bank when full or near the top of the crane, and pulls the spring latch of the bottom door of the dipper when in position for unloading, thereby dumping its contents.”
Steadily feeding coal into the boiler’s firebox, the fireman maintained the energy source. Managed by the cranesman, the labourers were assigned exhausting tasks, making sure materials to be scooped were within reach and not stuck too near for excavator reach. Unwieldy boulders, large tree stumps, and ledges were removed by blasting powder or dynamite, the choice of explosive dependent on the hardness of the material to be removed.
Labourers ensured a level surface for the machine in advance of laying the next sections of track, and attended “to the jack screws and blocking (to prevent the machine from moving) and to act as general utility men,” Hermann described. As well as the temporary rails for the machine, side tracks away from the main line were laid, to store empty and loaded train cars.
“The first Otis railway shovel had a single, one-cubic-yard bucket on an articulated arm,” wrote Robert Bradford in Keeping Ontario Moving: The History of Roads and Road Building in Ontario (Dundurn Press, 2015). Using steam-propelled chain hoists, winches, and ropes, the cranesman could “move the bucket from side to side and release it.”
By the 1870s, improvements included replacing chains with steel cables. Companies such as Bucyrus and Vulcan brought competition and fresh inspiration to the steam shovel market; by the 1910s, gas-operated excavators were available.
Augmenting the construction boom of the industrial revolution, steam shovels worked not only with railroads, but marine firms, mining companies, and material handlers. The machines excavated harbours, cleared canals, and prepared terrain for urban expansion.
Grand Trunk Railroad employed steam shovels across Ontario and the country to prepare for construction of Canada’s railways. As well as roadbed clearing, machine operators loaded material for track ballasts. Building a stable base to secure rails, ballast was the soil and rocks packed under, between, and around the wood railway ties.
A hydraulic steam shovel system was developed in 1882 by England’s Sir W.G. Armstrong. Using water to perform hydraulics, the system was tried at Hull dock works. The system failed. The first fully-hydraulic excavator was patented in 1897 by the Kilgore Machine Company of Minneapolis, Minnesota, stated Keith Haddock in Giant Earthmovers: An Illustrated History (MBI Publishing, 1998). “This machine used direct-acting cylinders, dispensing with all ropes and chains.”
Another technological leap occurred when Ferwerda Brothers of Cleveland, Ohio “mounted a hydraulic, telescoping boom excavator on a truck in 1940,” said Bradford. The patented design was flexible, “and especially useful for contractors doing municipal road and sewer work.”
The race for improved digging equipment was on. A mass of metal, cables, and cogs, early steam shovels carved the pathway for modern excavators, conveniently compact, powerful, and much less complicated to operate.
© 2020 Susanna McLeod. McLeod is a Kingston-based columnist who specializes in Canadian history.