In the mid-1950s, a concept took shape in Soviet mechanical engineering that, from the point of view of classical automotive logic, seemed almost absurd — a single-axle tractor. At its core, it was a universal chassis-transformer designed to perform extremely heavy work. Behind the external simplicity and even clumsiness lay an unexpectedly profound idea: to create an autonomous energy module on wheels, devoid of anything superfluous.
The paradoxical nature of this scheme was more visual than engineering. The single-axle tractor represented the maximum concentration of function: a minimum of metal and structural elements — a maximum of realizable traction. The abandonment of the front axle reduced losses due to rolling resistance, and the entire mass of the machine was redistributed directly to the drive wheels via the hitch. The goal was extremely clear — to bring the traction machine to its functional limit.
The first embodiment of the idea was the MAZ-529, which emerged from the walls of SKB-1 in 1956. The project was led by V. E. Chvyalev — a designer who would later become known as the creator of missile carriers. He disguised the military perspective as purely civilian road construction equipment. The machine with a 120-horsepower YaAZ-204A diesel engine was a spar frame resting on two giant wheels, with a cab and engine compartment mounted on top.
The absence of a full-fledged elastic suspension was compensated for by low-pressure tires, which absorbed shocks and bumps off-road. This asceticism was a conscious choice. Driver comfort and cab equipment were considered secondary, while the engine, transmission, and hydraulics formed the main thing — an autonomous power unit capable of working with a wide variety of trailed equipment.
The key to the genius of the scheme was the articulated design. A powerful hitch, on which the semi-trailer rested, was located above the single drive axle. Two hydraulic cylinders, controlled by a conventional steering wheel, allowed the angle between the sections to be changed up to 90 degrees. This provided amazing maneuverability for a machine of this size. In essence, it turned out to be a front-wheel drive road train, where the tractor itself acted as a universal tug for interchangeable semi-trailer systems.
This solution was ideally suited to Soviet realities. Large-scale construction of hydroelectric power stations, airfields, and test sites was often carried out far from any roads, and the country needed equipment capable of pulling heavy working bodies where infrastructure was non-existent. The single-axle tractor became a direct response to the geography and size of the USSR.
In 1959, a new stage began — the production of the machine at the Mogilev Automobile Plant. The MAZ-529V modification received a two-stroke YaAZ-206A diesel engine with a capacity of 180 hp and a five-speed gearbox with a reduction gear. The curb weight increased to 9 tons, and fuel consumption reached 80 liters per 100 kilometers. The maximum speed was limited to 40 km/h, but for equipment whose work took place off-road, this was not considered a serious drawback. Outstanding cross-country ability and traction had to be paid for with noise, vibration, voracity, and low transport speed. As a result, the MoAZ remained a highly specialized machine, poorly adapted to universal use.
Further development followed the path of specialization and unification. A lighter 529E appeared for military needs, as well as civilian versions 529B, 529G, and 529D with 205-horsepower engines, designed to work with nine-cubic-meter scrapers and earth-moving trolleys with a carrying capacity of up to 20 tons. Each modification solved strictly defined tasks. In engineering and construction units, these machines became indispensable, demonstrating exceptional cross-country ability where ordinary equipment was powerless.
At the same time, the driver's work required special skill. Articulated steering, inertial delays, and the "breaking" kinematics of the road train did not forgive mistakes. The MoAZ was not equipment for a random person — you had to get used to it and learn to feel the machine.
The culmination of development was the MoAZ-546P, launched into production in 1969. It received an angular cab and a YaMZ-238A diesel engine with a capacity of 215 hp. For the first time for single-axle tractors, a leaf spring suspension of the drive axle was used, which was a noticeable step towards increasing comfort. In the troops, this machine was used to tow missile launchers, heavy 8T26 cranes, and airfield equipment.
Soviet single-axle tractors became the pinnacle of the development of the idea of a specialized machine for heavy off-road conditions. Although similar single-axle solutions existed abroad, including for working with scrapers, the approach of Soviet engineers was noticeably more radical. They deliberately abandoned the universal self-sufficient tractor along the lines of heavy multi-axle Euclid or LeTourneau machines, designed for relatively prepared sites. Instead, the path of a highly passable road train was chosen, where the tractor acted as a pure "energy module", and all equipment and payload were placed on a semi-trailer. This ascetic but extremely expedient scheme precisely corresponded to the resource and logistical conditions of the USSR.
Over time, the concept of single-axle tractors became a thing of the past. The increase in the power of classic multi-axle chassis, the development of transmissions, and changes in logistics made such a scheme redundant. However, the ideas themselves — modularity, separation of functions, and the road train as a single system — have not disappeared. These "one-legged toilers" with their extreme simplicity and impressive functionality remained a symbol of the era when Soviet designers found ingenious solutions in the most unobvious engineering concepts.