Caterpillar's come out with a new line of electric-drive mining trucks called the AC Series, and some diesels that belch less pollution than the other ginormous vehicles the company builds. Depending upon your perspective, this is either the most half-hearted greenwashing attempt since Emirates ditched paper products but kept onboard showers, or the most amazing engineering feat since the Manhattan Project.

Caterpillar rolled out its new behemoths this week during the 2008 MINEXpo show in Las Vegas, and company president Stu Levenick crowed, "New technologies have allowed us to make trucks more reliable, easier to maintain and more friendly to the operator and to the environment," though we don't see how chopping off mountaintops is friendly to the environment.

Though Cat's new 795F AC is more mind-boggling than vegan pork rinds, it's still a flippin' huge truck that can haul 345 tons of earth out of a thousand-foot-deep pit using diesel-electric drive.It's even bigger than the 793D shown above (Cat hasn't released pics of the 795F, which is expected to go into production in 2010). The tires cost more than most cars on the road, and the thing has a flight of stairs to reach the cab. We still love it, even though there's no denying that a lot of these trucks will be put to use in ways that make the Sierra Club cringe. We can almost hear the sales pitch: "Ah, grasshopper! You must save the earth to destroy the earth."

Though some overly optimistic A123 fans predicted the AC-series would run on batteries or catenary wires, it relies on a diesel generator to support the electric drivetrain. Such a setup is nothing new, as Caterpillar developed AC-drive for mining trucks back in the 1960s, and Komatsu and others have been using it for years. But Cat's trucks are the biggest that can use either powertrain. The company says the leviathan EVs will appeal to an important niche market. "Cat will produce mining trucks for every application – uphill, downhill, flat or extreme conditions – and now with electric as well as mechanical drive," says Chris Curfman, president of Cat Global Mining and vice president of Caterpillar Inc.

Their impact on the environment, for better or worse, isn't the prime motivator for building these earth-moving beasts. The companies that use them are concerned with another kind of green, and that's operating costs. The electric drivetrains are cheaper to run because they produce gobs of torque at low speeds without straining mechanical transmissions, and they don't rely on mechanical brakes to slow their descent into the mine. What's more, electric drive trucks are easier to control, thereby increasing operator safety and reducing the risk of accidents. Plus, saving a little bit of diesel never hurt anyone. After all, the standard 795 has an 1,800 gallon fuel tank.

UPDATE 4:30 P.M. PST - We incorrectly noted that the 795F was the "world's biggest" EV. A couple of readers pointed out the error of our ways, and we've fixed it.

Photo courtesy Flickr user boeke, video courtesy MINExpo 2008.