130 Years of Caterpillar’s Manufacturing in South Milwaukee

  • Editorial Team
  • Excavators
  • 4 October 2023

More than 32,000 machines have been built at Caterpillar’s manufacturing facility in South Milwaukee during the course of its 130 years of existence. There were only 44 states in the nation, Grover Cleveland was president, and college basketball was playing its very first official game when the plant actually opened in 1893 to upgrade and expand the production facilities of Bucyrus Steam Shovel and Dredge Company. More than 200 of Caterpillar’s 120-tonne (134.4-ton) capacity electric rope shovel types have been manufactured at the site since the company acquired Bucyrus in 2011, first as Bucyrus and then as Caterpillar.

Caterpillar’s Contribution to Major Projects

According to Jeremy Niedens, facility manager at South Milwaukee for Caterpillar the company is proud of its long heritage in South Milwaukee, the impact the equipment produced at this location has had on the global market over the last 130 years, and the talented and dedicated team continuing the tradition of excellence in the production and support of Cat electric rope shovels and draglines.

Panama Canal in Bucyrus

Some major excavations, like the Panama Canal, have used equipment made at the defunct Bucyrus South Milwaukee factory.

Other Projects

The California Gold Rush, the New York State barge canal extension project, the greatest U.S. earthmoving project between 1902 and 1912, and the Panama Canal all involved the use of equipment made at the South Milwaukee plant.

Records kept by the corporation show that a total of 77 Bucyrus 40 to 50 ton steam-powered shovels were employed in the construction of the Panama Canal.

101 of the 102 shovels used to dig the canal were from Bucyrus when paired with the ones made by Marion Steam Shovel Company, a Bucyrus heritage company.

Cat Equipment Used in WWII

Europe saw an unparalleled need for excavators during World War II, and from 1942 to 1945, nearly all of the company’s output was used for the war effort. Following the war, the business started a 2 million dollar effort to double factory capacity. By the middle of the 20th century, Bucyrus had grown into a multinational corporation with a wide range of products. More than 166 countries had used more than 74,000 Bucyrus machines.

The Need for Advancements

Those early models, which were pushed on rails or rollers, would not be considered mobile by today’s standards. The machines had to be moved manually, which was very, very ineffective. Early advancements made at Bucyrus’ South Milwaukee site are credited with improving the effectiveness and toughness of rope shovels.

The steam powered shovels incorporated spinning belts in the shape of tracks from Caterpillar’s 1920s technology to greatly improve movement. Prior to the 1930s, the whole frame of the rope shovel was riveted; however, welds were used in their stead for some additional durability. Bucyrus also invented the use of electricity as a power source in 1917 using a DC method. By the year 1939, the switch from steam to electricity was complete.

Focus on Electrification and Sustainability

According to Flor Rivas, Cat product value stream manager the modern day mining industry is increasing its focus on the electrification of heavy equipment to reduce carbon emissions and boost efficiency. And he added that caterpillar is proud to be the leader in a product line that has been electrified for several decades.

The switch to less complex and more durable AC electric motors ultimately revolutionized the market for Bucyrus and the sector.

Mike Haws, technical steward for Cat Electric Rope Shovels was of the opinion that the introduction of insulated gate bipolar transistor (IGBT) fuseless technology led to the evolution into digital gate turnoff (GTO) systems. Bucyrus was on the cutting edge of AC drive technology thanks to a relationship with Siemens in the 1970s, which increased drive system availability to 99%.

Improvements made by Cat

In order to more effectively disperse the heat produced by electrical components, Cat quickly after the acquisition in 2011 designed a liquid-cooled motion regulator cabinet. This made it possible for the global product to work consistently at heights of up to 5250 m (17,220 ft), in temperatures ranging from -40 C/F to 50 C (120 F), and in extreme temperatures. Plus, the business unveiled a quicker propulsion transfer switch to increase productivity by reducing lag time by 70 percent.

Operator Assist

Enhanced Motion Control for the Cat 7495 was introduced in 2016 after Cat conducted a thorough analysis of the operating practices of operators with various levels of ability. The program offered machine security and made operating simpler. When the operator tried to swing the dipper through the bank, the program automatically reduced swing forces to protect the dipper. In order to speed up machine cycle times and increase production, it also protected the crowd ropes, brakes, and avoided boom jacking problems. Today, new technologies are still being developed in order to increase productivity and save costs.

The Integrated Technology Package (ITP) and the most recent Operator Assist Package (OA) are two new technology packages for ERS models that Cat introduced this year. ITP and its modules act as the building blocks for the introduction of present and future technologies by eliminating the requirement for extra in-cab displays from one-off tech packages. The operational technologies from Cat MineStar Solutions that support tracking, monitoring, and managing the shovel are also more easily integrated and installed more quickly.

Also, the most recent operator assistance package provides more sophisticated machine protection and easy operation. It has a LiDAR vision system, similar to the equipment used in autonomous mining vehicles, to scan the front of the shovel, preventing unintentional contacts between the dipper and the shovel.


The Cat 7495 has a 20-year average lifespan and is used in some of the most difficult operating environments, including the dry Chilean deserts with a yearly average rainfall of less than an inch and the subfreezing oil sands of Canada.

Over 105 billion tonnes of material have been handled by approximately 237 machines, including the Bucyrus 495 and Cat 7495 series, between 1990 and 2022.

For comparison, if this much were transported by the 364-tonne Cat 797 mining truck, it would require almost 13.9 million hours to finish and result in 290.1 million truckloads, given a 2.88-minute cycle and truck spotting time.