The T-40 amphibious scout tank was an amphibious light tank used by the Soviet Union during World War II. It was armed with one 12.7 mm (0.5 in) DShK machine gun. It was one of the few tanks that could ford a river without a bridge.
It was primarily intended to equip reconnaissance units. A land-based version of the T-40, the T-40S, was produced, although was later redesignated the T-60. The T-60 was cheaper, simpler, better-armed, and could fulfill most of the same roles, so T-40 production was halted.
The vehicle served mainly in Operation Barbarossa and the defense of Moscow, and it was rarely seen after that point, although it was used in Soviet training schools until 1946. A total 44 examples of the type were later fitted with Katyusha rocket launchers, firing 82 mm unguided rockets from a 24-rail launcher.
Amphibious capability was important to the Red Army, as evidenced by the production of over 1,500 amphibious tanks in the 1930s. The T-40 was intended to replace the aging T-37 and T-38 tank light amphibians. It was a superior design, but due to the pressures of war the Soviets favored the production of simpler tank designs, so only a small number of T-40s were built.
From 1961 until 1995 the T-40 was a farm tractor built by the Lipetsk Tractor Plant.
The T-40 was designed for plowing light soil, processing row crops, mowing, plowing snow and for transportation. To achieve these goals, it has a carrier transmission and rear axle, a more rigid connection between the engine and the transmission case, increased diameter of the rear drive wheels, smaller front guide wheels and stiffer suspension than other tractors.
Its durability has enabled many of the tractors produced in the 70's - 80's to remain in operation. Spare parts are still being produced.
The T-40 was produced by the Vladimir Tractor Plant. The tractor has four-cylinder four-stroke diesel air-cooled engine: D-37 37 hp or D-144 50 hp. Depending on configuration, an electric starter or a gasoline starting engine (PD8), were used to start the diesel engine.
It was manufactured in four-wheel drive (T-40A) and rear-wheel drive versions. It has an adjustable gauge and adjustable ride height on all wheels. The T-40 can be fitted with removable rear wheels of reduced width to work in aisles. In order to work on steep slopes, the track width can be increased by installing the rear wheels inside out.