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Two Monster Machines — The ACCO Super Dozer, Motorgrader

Fri June 15, 2018 - National Edition
Katherine Devlin – CEG Editorial Assistant


The ACCO super dozer is loaded for transport from the Acco depot in Portogruaro to its new home on May 15, 2012.
(Mauro Dal Santo/Marco Castellan photo)
The ACCO super dozer is loaded for transport from the Acco depot in Portogruaro to its new home on May 15, 2012. (Mauro Dal Santo/Marco Castellan photo)
The ACCO super dozer is loaded for transport from the Acco depot in Portogruaro to its new home on May 15, 2012.
(Mauro Dal Santo/Marco Castellan photo)
Mariotto Transporti used a Man FE 38.460 6x4 to transport the dozer.
(Mauro Dal Santo/Marco Castellan photo) The undercarriage of the ACCO super dozer shows little wear.
(Mauro Dal Santo/Marco Castellan photo) Dino e Rino Valerio (seated) and friends atop the world’s biggest crawler dozer. 
(Mauro Dal Santo/Marco Castellan photo) The rear ripper measures 10 ft. and is powered by hydraulic rams.
(Mauro Dal Santo/Marco Castellan photo) The driver’s seat of the ACCO super dozer.
(Mauro Dal Santo/Marco Castellan photo) One of two 8-cylinder, 675 hp Caterpillar diesel engines combine for a 1,350 hp output.
(Mauro Dal Santo/Marco Castellan photo) The front piston of the ACCO super dozer
(Mauro Dal Santo/Marco Castellan photo) Mariotto Transporti transported the dozer to its new home.
(Mauro Dal Santo/Marco Castellan photo) he ACCO motorgrader — without cab, twin wheels and blade — built by Umberto Acco in 1980. 
(Mauro Dal Santo/Marco Castellan photo) A view from the cockpit of the world’s largest motorgrader
(Mauro Dal Santo/Marco Castellan photo) In 2012, an old friend and neighbor of Umberto Acco, Dino e Rino Valerio, who also is a collector of historic vehicles, saved the dozer from demolition.
(Mauro Dal Santo/Marco Castellan photo)

In the early 1980s, Umberto Acco, an entrepreneur and owner of a civil construction company in Portogruaro, northern Italy, received a job that would require his company to build a custom crawler dozer and motorgrader.

The machines needed to be big — really big — and were intended to be used on a project that involved moving earth — lots of earth — in large, desert areas.

While many components of the dozer had to be custom made, including the blade, Acco used mainly Caterpillar parts to build what has become known as 'Super Dozer'— the world's largest bulldozer.

As of 2018, it also is the most powerful tracked dozer ever made.

How Big Is Big?

The specs for the more-than-40-ft., 183-ton crawler dozer are dizzying. Two 8-cylinder, 675 hp Caterpillar diesel engines combine for a 1,350 hp output. The blade measures 23 ft. wide and 9 ft. high. The rear ripper (a claw-like device) measures 10 ft. and is powered by hydraulic rams.

The tracks were custom made by Berco. The transmission operates through two drive sprockets for each track to create torque generated from the engines. The brakes and control mechanisms are operated hydraulically. This massive piece of iron was the only one of its kind produced.

For comparison, Caterpillar's largest model, the D11 dozer, is 115 tons, 35.8 ft. long, 14.9 ft. wide, had a 22 ft. blade and operates at 850 hp.

The world's largest production dozer is Komatsu's D575A 168-ton, 1,050-hp dozer. This machine measures 38 ft. 5 in. long, 24 ft. 3 in. wide and has a 11 ft. 11 in. blade.

The Motorgrader

The world's biggest motorgrader also was created in 1980 for the same project. It had two engines: the 700 hp front end articulated from the 1,000 hp rear end. It measured more than 24 ft.; weighed 200 tons; had a 33 ft. blade; and had a total of 12 tires — two per hub.

While in storage, the machine became a tourist attraction. It did not survive its time in storage and has been dismantled and sold for scrap.

A Major Roadblock

The dozer and motorgrader were to be used for a massive earthmoving project in Libya. It is unclear whether the machines were to be used for a pipelaying project or for other land-development but just as the dozer was completed, Colonel Gaddafi encountered an embargo by the United Nations, which included trade restrictions. The ACCO dozer and motorgrader could not be shipped to Libya.

The dozer was operated only once on a job in southern Italy. However, the cost of transporting it was prohibitive and both machines were placed in storage and maintained at the factory where they were built.

Umberto Acco passed away in 2006 without appointing successors to the company. The decision was made not to continue with Acco's innovations and the business was shuttered. The property became a dumping ground for various earthmoving machines, including the giant dozer and motorgrader.

A Second Chance

In 2012, an old friend and neighbor of Acco, Dino e Rino Valerio, who also is a collector of historic vehicles, saved the dozer from demolition. He purchased the monster machine and arranged for heavy transport to a new location. Although Valerio passed away in 2012, today the dozer is safely stored and on display with the rest of his collection for public viewing at the family's Bejaflor nursery.

Sources for this article include:

facebook.com/AccoDozer/?ref=page_internal; en.wikipedia.org/wiki/Acco_super_bulldozer; forums.dhsdiecast.com/default.aspx?g=posts&t=120813; acmoc.org/bb/showthread.php?27525-The-ACCO; translate.google.com/translate?hl=en&sl=it&u=http://www.portogruaro.net/news/scheda.php%3Fcategoria%3D14%26news%3D30377&prev=search; khplant.co.za/blog/article/world%E2%80%99s-largest-motor-graders