TC-497 Mark II, the 170-meter long “highway train” that the US built more than half a century ago for remote regions

No, it is not a train. Or yes, depending on how you look at it. The colossus that you see on these lines with the appearance of a gigantic mechanical caterpillar is el TC-497 Overland Mark II, a railroad to circulate on land or asphalt, free of rails. It is also, in a way, one more of the follies that was lit up in the heat of the Cold War. At around 170 meters long, the equivalent of almost two 90-meter soccer fields, 54 driving wheels and a power of almost 5,000 horsepower, the Mark II – which only has its name as a child – is often presented as the largest SUV in history.

Its size, of course, is beyond conventional measures.

The million dollar question is: Why would anyone want to handle such a hulk? In the midst of the Cold War and with the memory of Korea still very much alive, in the mid-1950s the governments of the United States and Canada decided promote the Far Early Warning Line, la DEW, a row of radar stations bordering the arctic circle. The strip would circulate through the north of Canada and Alaska and would extend to Greenland and Iceland. Its objective was to detect any USSR bombers that approached the North Pole and could threaten North America.

Mission: operate in inhospitable regions

On paper the idea was magnificent, but when translating it into reality the US authorities encountered a practical problem. How to build it? How to move the material and operate in one of the most remote regions of the planet? To solve the ballot, the US Army Transportation Research and Development Command (Tradcom) proposed to use the inventions of Robert Gilmore LeTourneau, a prolific inventor from Vermont who was noted for his earth-moving ingenuities and who had perfected a kind of diesel-electric transmission for heavy machinery with multiple wheels.

Some time ago LeTourneau had presented the VC-12 Tournatrain, a kind of land train designed to circulate without tracks, equipped with a 500 horsepower Cummins diesel engine connected to a generator, capable of pulling several cargo trailers and — most importantly, perhaps— a 16-wheel drive traction system. To reinforce their capacity, the design contemplated that each one of them was driven by electric motors that obtained power from the generator.

The engineer had in mind dedicating it to logging operations. The VC-12 was refined with a second version with additional trailers and a control cabin, plus a second Cummins that gave the set a total power of 1,000 horsepower and 32 drive wheels.

Amazed, the US authorities commissioned him a new prototype adapted to the needs of those responsible for the DEW line. LeTorneau’s response was what one might expect: redoubled the reach of his machine. The one baptized as TC-264 Sno-Buggy, equipped with gigantic wheels of around three meters high, was released in Greenland in 1954, and left a good taste in the mouths of the army and Alaska Freightlines, the company contracted by Western Electric for the transfer of merchandise to the northern regions. So much so that over the following years the company would develop new models, such as the VC-22 Son-Freighter, which was dedicated to transporting hundreds of tons of cargo for the DEW Line.

LeTourneau’s style must have particularly appealed to the US military. Encouraged by the good results of the Logistic Cargo Carrier (LCC-1) —A huge machine that was used for years to haul cargo across Greenland — the US knocked on the Vermont engineer’s door again. The result was the gigantic off-road vehicle TC-497 Overland Train Mark II, just over 170 meters long and equipped with a nine-meter high locomotive and a dozen steerable four-wheel-drive wagons. Taken together, the Mark II reached a total of 54. Power was provided by four 1,170-horsepower gas turbine engines.

The wit premiered in the early 1960s and it could have been even higher. LeTourneau devised it so that it could pull an unlimited number of wagons. If you wanted to add more units, you only had to accompany them with units with fuel and an engine. To make it easier to handle – especially at the angles – the trailers were equipped with steerable wheels. It is calculated that he was capable of transporting 150 tons at 20 mph — about 32 kilometers per hour — for trips exceeding 600 km. Or even more, if the fuel was increased.

Another of its novelties it was that it replaced Cummins engines with gas turbine engines of greater power and less weight. Unlike the LCC-1, with a single 600 hp engine, the Overland Train had four 1,170 hp Solar 10MC engines, one in the “control car” and three others scattered throughout the train. Its huge cockpit was not articulated and six crew members could travel inside with all kinds of comforts, including rest, toilet and food preparation areas.

However, neither its cyclopean size nor that versatility helped it last too long. Despite the good results of the initial tests, in 1962, some voices assure that the Mark 2 never left the Arizona proving ground for combat duty on the ground. There are those who also point out that the most extensive model it reached around 180 meters.

The Mark II was stunning, true; but not nearly as practical as heavy lift helicopters, perfectly capable of reaching remote regions like Greenland. At the end of the 60s it was given a ticket, part of its structure was sold as scrap metal and the cabin ended up being exhibited in the Yuma Proving Ground Heritage Center, a military museum.

We still have, yes, its impressive dimensions.

And photos worthy of the Mad Max universe.

Via | Top Speed