A Brief History Of The Crawler Tractor

The age of steam power allowed the development of traction engines for pulling agricultural implements and wagons.   Steam engine powered traction engines were equipped with wheels whose high ground pressure and limited traction were an impediment in soft ground applications.  Attempts to overcome these challenges resulted in employing ever larger wheels, both in diameter and width requiring increasingly larger machines to propel them.   As the machines grew they reached Titanic proportions and became clumsy and difficult to maneuver.  Replacing the wheels with tracks resolved the issues of high ground pressure and poor traction and resulted in smaller more nimble machines.   The tracks lowered ground pressures gave better traction and with the advent of internal combustion engines allowed for smaller more powerful traction machines.   Many of the early applications for tracked engines or crawlers were for agricultural purposes where soft ground and the need for good traction for pulling agricultural implements are critical issues.    However, the potential of the crawler as an earthmoving machine was soon realized and before long crawlers were being equipped with simple dozing blades, heralding the birth of the bulldozer.   The milestones in the history and development of the crawler tractor are many.

Here are just a few.

  • 18th century  invention of the steam engine
  • 19th century development of wheeled, steam driven traction engines to pull loads and agricultural implements.
  • 20th century – 1904 Holt Manufacturing Company replaces two drive wheels on their steam traction engine with tracks, keeping the front wheel for steering.
  • 1906 Holt Manufacturing Company markets their first steam driven crawler.
  • 1925 – a hydraulically controlled blade is built by the LaPlant- Choate Manufacturing Company as a dozer attachment.
  • 1925 Holt Manufacturing Company and C.L. Best Tractor join forces to create the Caterpillar Tractor Company.
  • 1935 Caterpillar builds the RD8 tractor which evolves into the iconic Caterpillar D8 series of tractors.
  • 1947 Allis Chalmers builds the HD-19 the largest crawler tractor to that date.
  • 1947 International Harvester introduces the TD 24 overtaking the AC HD19 as world’s largest crawler to date.
  • 1954 September – GM takes over ownership of the Euclid Corporation and in 1955 markets the world’s largest bulldozer to date the twin engine TC-12.
  • 1962 International Harvester builds the TD30 – setting a new record for world’s largest crawler.
  • 1963 Allis Chalmers regains record again for building the world’s largest crawler – the HD-41 weighing 70 tons with 524 horsepower engine.
  • 1968 General Motors earthmoving division Euclid is renamed; GM dozers are marketed under the new name Terex.
  • 1977 Caterpillar introduces the D10 – first Caterpillar model featuring the high drive system.
  • 1980 Caterpillar introduces a second tractor featuring the high drive system – the D9L.
  • 1982 International Harvester sells construction machinery division which then becomes the International Hough Division of Dresser Industries.
  • 1982 Caterpillar replaces conventional drive D8K with high drive D8L.
  • 1986  Caterpillar replaces the D10 with the D11N
  • 1987 Caterpillar introduces the D8N – the first Caterpillar tractor employing differential steering.
  • 1996 Caterpillar introduces the D11R and D11R Carrydozer featuring an innovative blade designed to carry as well as push material.
  • 2009 Caterpillar takes bulldozers to a new technological level with introduction of the diesel electric driven D7E model which offers increased production with less maintenance and fuel consumption than previous D7 class bulldozers.

Today bulldozers still occupy an important position in the hierarchy of earthmoving equipment.  Some work, formerly the sole domain of bulldozer, is now being performed by other classes of earthmovers such as hydraulic excavators.  However, with confidence, we can predict this most essential machine will continue to evolve and retain a vital role in the construction, forestry and mining industries.

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