A look at the Overland Train

In the early 20th century, Robert Gilmour LeTourneau established his company in California, initially building earthmoving equipment for his own contracting business. The equipment soon garnered the attention of others in the earthmoving business, leading LeTourneau to begin marketing the equipment he designed. The company quickly became known for three distinctive characteristics: innovation, massive scale, and the use of electric drive systems in its machinery.

The birth of the “land train” concept began in February 1953 with the Tournatrain— an articulated vehicle consisting of four units with 16 powered wheels, capable of carrying 60 tons. Within a year, LeTourneau expanded this design to include 8 units, 32 driven wheels, and doubled its capacity to 140 tons, powered by a 1000-horsepower engine. This caught the attention of the Army’s Transportation Research and Development Command, who were seeking vehicles capable of moving heavy loads across snow-covered terrain.

The first commercial application came from Alaska Freight Lines, who ordered a specialized version called the VC-22 Sno-Freighter for delivering components to the Distant Early Warning (DEW) line. This massive machine featured 24 electrically driven wheels, powered by twin Cummins V-12 diesel-driven generators, and could carry 150 tons of cargo across six units. However, the $450,000 vehicle’s career was brief; after just two successful trips, it suffered a catastrophic accident while descending a steep grade, followed by an engine fire. The abandoned vehicle remained in the Yukon for five years.

Despite this setback, the Army saw potential in the concept and in 1955 contracted LeTourneau to build the Logistical Cargo Carrier (LCC-1), designated by the company as model YS-1. This 173-foot-long behemoth consisted of a power unit pulling three trailers, each capable of carrying 15 tons. Power came from a Cummins VT-12 diesel engine-generator, which supplied electricity to motors in each of its 16 10-foot diameter tires — special units originally developed for an earlier project called the TC-264 Sno-Buggy.

The vehicle’s maintenance was carefully considered in its design. A powered crane mounted at the rear of the control car facilitated the challenging task of changing the massive Firestone 48x68 tires. These weren’t ordinary tires - they were specially designed by LeTourneau and custom-molded by Firestone to meet the unique demands of Arctic operation.

The LCC-1 underwent extensive testing — first in Texas, then Michigan, followed by 2,000 miles of service testing in Greenland, and finally in Alaska. These tests were key to refining not only the design, but the entire concept of an overland train.

• Early tests showed the vehicle’s remarkable ability to traverse snow with minimal ground pressure, despite its massive size

• The Army later added features including a snow deflector and a steel frame for mounting radar navigation equipment

• A significant upgrade came with the addition of a power car at the train’s rear, which provided additional electrical capacity for the wheel motors

• The vehicle proved its worth during Exercise Willow Freeze in 1961, successfully crossing a specially constructed ice bridge over the Gulkana River in Alaska

The tests proved successful enough that the Army proceeded with its ultimate goal: the TC-497 Overland Train Mark II.

The TC-497 was truly extraordinary. At 572 feet long — officially recorded as the longest land vehicle ever built — it weighed 300 tons empty and 450 tons fully loaded. Designated the Overland Train Mark II, the TC-497 represented a complete rethinking of the land train concept. Its control car featured panoramic windows and a more streamlined design, with the cab set behind the front wheels. The most significant advancement was its propulsion system; instead of diesel engines, it employed four Solar 10MC gas turbine engines, each producing 1,170 hp, to generate electricity for the 54 wheel-mounted traction motors.

The control cab included living quarters for six crew members, complete with sleeping areas, toilet facilities, and a galley. It even featured radar equipment for navigation. Each cargo car could transport 15 tons, giving a fully configured train with ten cargo cars a total capacity of 150 tons. The vehicle could maintain approximately 20 miles per hour on level ground - a remarkable achievement given its size and the terrain it was designed to traverse.

Completed in February 1962, the TC-497 was tested at the Desert Proving Ground in Yuma, Arizona. Despite its Arctic-oriented design, desert testing was crucial as the vehicle was intended for multiple climate conditions. Despite successful testing at Yuma Proving Ground, the project ultimately fell victim to changing military priorities and budgetary constraints as the Vietnam War demanded increasing resources. Accordingly, Arctic testing never occurred, and the TC-497 remained in Yuma. In 1971, it was sold at auction, with only the power car surviving today at the Yuma Proving Ground Heritage Center - the last remnant of this ambitious transportation project.

The Overland Train project represented a unique chapter in transportation history, pushing the boundaries of what was possible in overland cargo movement across extreme terrain. This comprehensive testing and development program, while ultimately not entering full production, demonstrated significant technological achievements in electric drive systems, Arctic mobility, and large-scale vehicular design that would influence future transportation projects. 

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