How Steam Shovels Work

By the 1800s, inventors were taking advantage of steam energy to power all types of mechanical devices. One such brilliant inventor was William Otis, who designed a machine to dig faster and more efficiently than the teams of men employed for railroad-building projects. While only in his 20s Otis (a cousin of the elevator entrepreneur Elisha Otis) received a U.S. patent for the steam shovel -- the first of its kind -- in 1839.

He died that same year of typhoid fever, at age 26. It would be several decades before steam shovels could make a significant mark on the landscape though, as the Otis family tightly controlled the patent behind the technology.

But eventually, other inventors and companies sprang up with their own steam shovel designs to feed the exploding demand to move earth faster -- a demand created by railroad expansion in the United States and elsewhere.

The first "full-swing" steam shovel -- one in which the bucket and arm could swing a full 360 degrees, was invented in England in 1884 and brought new versatility and value to the machines. This advance was followed by others, including wheels that didn't have to be mounted on rail tracks to move the equipment; steel cable that was more durable than the chains used to operate the hoisting mechanisms; and increasingly larger shovel sizes that could perform bigger jobs.

The Marion Steam Shovel Company, founded in 1884, in Marion, Ohio, sprang up in direct response to the railroad boom that opened up the western United States and Canada. By the early 1900s, Marion was such a dominant steam shovel manufacturer that the town came to be known as "the city that built the Panama Canal," for the crucial role steam shovels played in that massive undertaking [source: Ohio History Central].

Another power player in the steam shovel business, Bucyrus Foundry and Manufacturing Company (established in 1880), committed itself to excavating machinery in 1896 as it became obvious what profit potential lie in steam shovels and other heavy digging equipment. Bucyrus, too, could lay claim to pitching in on some of the most ambitious engineering projects of the time -- including the Panama Canal. According to the company history, 77 Bucyrus shovels were used for the historic dig connecting the Atlantic and Pacific oceans [source: Bucyrus International].

Company lore even has it that President Theodore Roosevelt climbed aboard a 95-ton Bucyrus steam shovel while inspecting progress on the Panama canal in 1908.

Bucyrus, in one of the most common ironies of business, wound up buying one of its biggest longtime rivals, Marion (by then named the Marion Power Shovel Company), in 1997.

Are you ready to dig beneath the surface and find out how these mammoth machines operate?

So how exactly do these boiling behemoths work? As you might guess, the driving force behind them is their clever use of steam, starting with the boiler and gigantic water tank.

Usually a second person, often called a fireman, would have the express job of tending to the boiler: stoking the flames with coal and maintaining pressure at just the right amount to provide steam needed to power movement and operation of the shovel.

From the boiler, steam traveled down a pipe to one or more cylinders. In the cylinders, the high-pressure steam drove pistons, which in turn supplied mechanical power for the steam shovel's subsystems, including a main engine, winch and "crowd engine."

Closer to the "business end" of the shovel sat the boom, dipper stick and bucket -- the mouth-like container that digs into material then releases it into an awaiting truck or other transport to haul the stuff away.

All this sat on a chassis that allowed the steam shovel to move from one location to another -- slowly. The first steam shovels were quite crude in this regard, running on metal tracks that workers had to scramble around and place in front of the vehicle when it was needed in a new location. Eventually the shovels would come to get wheels and later, caterpillar tracks that allowed them to move more independently [source: Haddock].

These hard-working machines helped build a world obsessed with economic growth, but after decades of popularity, they fell out of favor. Find out why on the next page.

So what happened to these once-dominant construction site fixtures? Did the industrialized countries of the world lose their appetite for large-scale projects?

Hardly. Steam shovels simply made way for more modern technologies. Diesel engines began to replace steam engines on a large scale in the 1930s. Also, the advent of hydraulic mechanical systems proved more reliable and efficient than the chains, cables and pulleys used for steam-powered machines.

The steam shovel didn't disappear from the landscape entirely. Because of their massive size, completely dismantling them wasn't easy. Many were abandoned after their work was done and can still be found at old quarries or mining sites, rusting away. Some were rescued and restored and survive as tourist attractions or museum pieces. Yet others have found their way into the hands of collectors who maintain them in working condition and show them off at events sponsored by the Historical Construction Equipment Association.

You can even find steam shovel scale models -- some of which actually work -- that celebrate the ingenuity that went into engineering the originals.

Steam shovels served as the predecessors to excavation machines that are still common today, from the tracked, drivable excavators seen at building sites to the towering, lumbering drag line excavators used for mining operations.

To unearth lots more information about steam shovels, follow the links on the next page.