Behind the World’s First Electric-Drive Dozer

Caterpillar is one of the world’s leading manufacturers of construction and mining equipment, diesel and natural gas engines, industrial gas turbines, and diesel-electric locomotives. Since 1925, the company has been driving sustainable progress and helping customers build a better world through the innovative products and services it offers.

With the launch of its H-Series models in 1985, Caterpillar expanded its elevated sprocket undercarriage concept to its medium track-type tractor line.

The company’s D4H, D5H, D6H and D7H dozer models were the first to feature a high drive design — the popular lineup was rounded out with the addition of its D8L model in 1987.

Thirty-five years later, Caterpillar celebrated the production of its 175,000th medium dozer and the longevity of its elevated sprocket design in the medium dozer class by awarding three Caterpillar customers with commemorative units — two of which were the Cat D6 XE.

Continuing 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, featuring increased agility and 35% better fuel efficiency, compared to the previous three-speed model D6T.

A recipients of one of the D6 XE units was longtime Caterpillar customer and multi-unit dozer owner Goodfellow Bros. LLC, a fourth-generation, family-owned contractor based in Wenatchee, Washington, which celebrates its 100-year anniversary in 2021.

Shep Nelson is director of equipment and procurement at Goodfellow Bros. and is responsible for the purchase, sale and maintenance of over 1,000 pieces of heavy equipment and trucks, valued at over $100 million and in use on wide range of diverse projects across California, Oregon, Washington and Hawaii.

Goodfellow Bros. was founded in 1921 by three brothers who dreamed of building roads so that farmers could bring their crops to market.

Today, it is considered by its clients to be leaders of innovative solutions, Goodfellow Bros. welcomed the addition of the D6 XE to its expansive fleet. Throughout its many years and equipment purchases, Goodfellow Bros. has consistently owned Caterpillar machines, and highlighted some of the purchases in its anniversary timeline.

Former Goodfellow Bros. president Jim Goodfellow Sr. said the company’s 1942 Caterpillar D8s were “all very modern.” Goodfellow Bros. also spent time operating the prototype of Caterpillar’s first D10 with high track technology in 1976.

And, as the partnership continues, Construction Business Owner (CBO) dove into their histories and the D6 XE. We spoke with Nelson from Goodfellow Bros. and Patrick Kearns, Caterpillar’s North America industry region manager. The following questions and responses provide a deeper look into their extensive partnership.

CBO: Please share your first impressions and thoughts on being selected to receive the D6 XE commemorative unit.

SN: We were absolutely thrilled to be selected to receive the 175,000th D6. Our reps at Caterpillar explained to us that we were selected because of our long-standing history as a Caterpillar customer, but also because they were excited to celebrate our 100th year in business as a heavy civil contractor.

CBO: Tell us about your fleet. How many machines does Goodfellow Bros. currently own, rent and operate?

SN: We have a large variety of machines — around 500 pieces — that focus on earth moving and heavy civil. Additionally, we have about 500 trucks to support construction operations.

CBO: How’s the experience of using the D6 XE on the jobsite?

SN: So far, we have used the D6 XE extensively on the island of Maui in Hawaii. It is a great machine. It has tons of power and uses less fuel than the standard D6. It is very quiet, as it runs at a constant and low rpm, compared to a traditional machine. It is a great product all around.

CBO: How you found any difference in using an electric-drive dozer versus a standard dozer? What are some of the performance perks or problems?

SN: Electric engines provide much greater torque without having to rev up anything, so the power is incredible. We also are expecting lower repair costs because the diesel generator runs at a fairly low and constant rpm, and the final drives are just electric motors.

CBO: On the job, where do you see the D6 XE being most beneficial?

SN: Same application as any D6 with a variable blade, which is to say a lot of applications. The D6 is big enough to push a good amount of material, but the variable blade makes it a good finish Cat, too.

CBO: Where is the electric construction equipment market headed? What predictions do you have for this category of manufacturing in the coming months/years?

PK: Caterpillar engineers have developed industry-leading technology around electrification, autonomy, remote control, and telematics, all in conjunction with making the worksite more productive and, most importantly, safer. We’ll continue to work alongside our customers to identify challenges, understand requirements and deliver solutions that help them be more successful. The work they do — building and maintaining infrastructure, mining commodities, generating power and transporting goods — is essential and irreplaceable. Our job is to help them do it more sustainably throughout the life cycle of our products.

CBO: What are the most crucial components/specs of the special-edition high-drive electric Caterpillar D6 XE dozer?

PK: The D6 XE has a unique diesel/electric drivetrain consisting of a Cat C9.3B diesel engine, generator,
inverter and motor. This electric drive system allows the D6 XE to burn up to 35% less fuel than a traditional powershift while providing up to 10% more productivity.

CBO: What was the inspiration behind creating this machine and what are its ideal applications?

PK: The D6 XE was created as an update to the D7E, which was launched in 2009 as the first electric-drive dozer. The D6 XE includes updated technology and meets customer demands of the D6 size applications. These machines are excellent at heavy dozing, spreading, finish grading, slopes, just about any application for a medium-size dozer. It was created to be an “all around” machine that can perform almost any task and excel at it.

CBO: How do electric machines like this one compare to standard dozers when it comes to functionality and performance? What are the benefits to the operator?

PK: Electric drive dozers provide more torque than a traditional dozer, and run at a lower engine rpm, which delivers fuel savings for the customer. In terms of operation, the machines have the same cab and controls, so an operator can be comfortable and familiar with the D6 XE. Operator benefits include a variety of speeds to match the dozer to the work at hand, easy speed control, aggressive steering power and fast maneuverability.

CBO: Can contractors expect to see more electric equipment in development from Caterpillar in the future? If so, what’s the timeline?

PK: Caterpillar is always working with our customers to understand their needs and applications, and we will continue developing the best products to match those demands. Electric drive provides key values customers need, such as low fuel consumption, high torque and power, long life and easy serviceability.

CBO: What else should our readers know from Caterpillar?

PK: The electric drive system has significantly fewer parts than a traditional powershift, thus the cost of rebuild is lower. The powertrain also uses less fluid, and that fluid lasts twice as long, reducing future service costs. With the rebuild and second life of this dozer being less expensive, we expect customers to run these machines longer, providing them lower overall owning and operating cost. The Caterpillar team is passionate about building the best products, developing the best solutions and standing by the best customers. It’s what Caterpillar and our dealers have been doing for 95 years starting with the industry’s first-ever track-type tractor to the new D6 XE today.