It’s time for a pop quiz: Who built the world’s first electric-drive crawler tractor?

If you said Caterpillar Inc., you’d be close, but wrong.

Cat last year began producing the D7E, a diesel-electric tractor that cuts fuel consumption and is finding a wide range of uses, including construction and landfilling.

Call it what you like—a series hybrid, diesel-electric tractor, electric dozer—it all mirrors our society’s ongoing quest to make vehicles more efficient, limit carbon emissions and cut petroleum dependence.

Now, the Peoria, Ill.-based manufacturer says it will use its recent acquisition of locomotive outfit Electro-Motive Diesel Inc. to power up more vehicles with electrics.

Meanwhile, other big-name competitors have been selling hybrid construction machines—such as Komatsu’s excavator—generating attention from fleet owners looking to cut costs and go green.

Cat wasn't the first to head down this road. It was the Holt Manufacturing Co., one of the predecessors of the Caterpillar Tractor Co., which actually built the world’s first electric crawler.

Holt collaborated with G.E. in 1917 to produce the Holt Gas Electric Tank. Apparently, it was not only the first electric tractor but also the first American tank, Cat and other sources say. The machine even predated the widespread use of diesel engines, which did not gain popularity for heavy equipment until the 1930s.

The tank was powered by a four-cylinder, 90-hp gas engine mated to electric motors on each track. Pliny Holt, who founded the East Peoria Holt plant, spearheaded the effort while working at the U.S. Army Ordnance Dept. Only one prototype was built.