In 1985, Caterpillar expanded its revolutionary elevated sprocket undercarriage concept to its medium track-type tractor (MTTT) line with the launch of the H-Series models.
Still unique to this day for the 130 to 350 hp (100 to 250 kW) dozer class, the high drive design conformed to the ground better, improving durability, serviceability and performance compared to low-drive and oval track designs.
The Cat® D4H, D5H, D6H and D7H dozer models were the first to feature the high drive design, and in 1987, the D8L model was added to the family. In addition to bringing many of the same large dozer advantages to the medium line, the elevated drive sprocket allowed movement of the front and rear track idlers. This helped to fine-tune machine balance and ground pressure for specific applications more easily than oval track machines. For the first time, variable pitch angle tilt (VPAT) blades were made available to high drive dozers with the D4H and D5H models for finishing jobs faster by grading at higher speeds.
Thirty-five years later, Caterpillar celebrated the unrivaled success of the elevated sprocket design in the medium dozer class by producing three commemorative 175,000 units in May 2020. “One of the original taglines to promote the early high drive tractors was ‘Beyond Known Capabilities,’ because these units set a new standard for efficiency, productivity and ease of operation,” says Wes Holm, chief engineer, Caterpillar medium tractor products.
“With our next generation medium dozer line, which includes the new D5, D6 and D7 models, we continue to push these envelopes through adaptation of technology to drive productivity and efficiency to another level.”
Three commemorative Cat® tractors built
With travel and gathering restrictions resulting from the ongoing coronavirus pandemic, Caterpillar cancelled in-person celebrations to mark the historic 175,000-unit milestone for its medium dozers. However, three customers took possession of the commemorative units, which feature special decals on the fenders denoting the 175,000-unit milestone. The 175,000 image appears inside the cab as well, where it is embroidered on the headrest and printed on a plaque denoting each unit’s limited-edition status.
Built in East Peoria, Ill., the first two commemorative units were Cat D6 XE electric drive dozers, featuring a sleek dark gray and black paint scheme. The third unit, a D6 dozer with 4-speed, fully automatic transmission, is finished in traditional Cat yellow with special black tracks and blade.
Symbolic of the medium dozer line’s long history of innovation, the Cat D6 XE is the world’s first electric drive dozer to offer the elevated sprocket design. It boasts a strong, yet light, structure, providing optimum machine balance for grading without the need for a rear implement or counterweight. Integrated Cat GRADE technologies, such as standard Slope Assist and available Cat GRADE with 3D, help to increase overall jobsite productivity by up to 50 percent. Offering up to 35 percent improved fuel efficiency, the dozer features a durable design with updated components, long service intervals, and extended scheduled maintenance to reduce service and maintenance costs by up to 12 percent.
Long-time Caterpillar customer and multiunit Cat dozer owner, Goodfellow Bros., a fourth-generation, family-owned contractor based in Wenatchee, Wash., received one of the D6 XE units. Before being put in the dirt in Hawaii, Goodfellow plans to feature the new commemorative dozer in the company’s 100th anniversary celebration, planned for 2021.
Holt Cat of San Antonio, Texas, took possession of the second commemorative D6 XE dozer. The Caterpillar-Holt longstanding relationship dates to the company’s origins when Benjamin Holt invented the Caterpillar track-type tractor in 1904. The D6 XE dozer design embodies 116 years of continued innovation since Holt’s original Caterpillar. The dealership plans to use it to help promote Cat Next Generation Dozers at future customer events.
The commemorative D6 dozer was shipped to Canadian dealer, Finning Cat, where it was sold to Midwest Pipelines Inc., based in Spruce Grove, Alberta. The legacy of Cat MTTT ownership can be traced back 39 years to Midwest’s sister company, Pidherney’s Inc. of Alberta, when founder Merv Pidherney purchased his first dozer, a Cat D6D. Today’s combined dozer fleet is nearly 100 strong, and the companies remain family owned and operated, specializing in oilfield, civil and hauling projects.
Cat D6 and D6 XE dozers are manufactured exclusively in East Peoria, Ill., and Grenoble, France, along with other models in the medium dozer line. In addition, Caterpillar manufactures Cat medium dozers in Piracicaba, Brazil, and Rayong, Thailand, to meet global market needs.