Lacking the know-how to design and develop modern battle tanks, the Soviets imported German engineer Edward Grote to solve their modernization requirement of the 1930s. This partnership led to several experimental designs of which the TG-1 Medium Tank was just one result. The tank had several interesting features for the period but was deemed ultimately too costly to mass-produce when there were other cheaper alternatives available to the Soviet Army. As such, the TG-1 existed as nothing more than an experimental entry in Soviet armor lore.
With work beginning at the Bolshevik Works of Leningrad in 1930, the 25-tonne tank utilized welded plate construction as opposed to riveted and its frontal face received 50mm thickness for maximum protection. To aid in steering, a hydropneumatic system was installed and drive power was to come from a still-to-be-developed 300 horsepower gasoline-fueled unit. Dimensions included a length of 6.5 meters, a width of 2.8 meters, and a height of 3 meters. The crew would number three.
Instead of a traditional turret over the hull, the TG-1 showcased a fixed casemate with a small, independently-operated turret atop it. The casemate was fixed as part of the hull proper, and positioned at the center of the design, housing the main armament consisting of a single 76.2mm PS-3 cannon. This was straddled by a 7.62mm DT machine gun (to each side) and each casemate side facing, as well as its rear facing, also showcased a single 7.62mm DT machine gun mounting (for a total of five DT machine guns). The small turret atop the casemate was home to a single 37mm PS-2 cannon and, above this, a commander's cupola further extended the height of the vehicle. All this gave the tank considerable fire power and, to an extent, situational awareness when compared to contemporaries.
The pilot form was completed in June of 1931 but its intended 300 horsepower engine was not yet available so the M-6 8-cylinder gasoline-fueled model was used instead. In testing, the design proved sound on-the-whole though there were noted issues with the drive train, fighting compartment (the crew of three was required to do quite a bit between them), and suspension system. The vehicle was tested up to speeds of 35 kmh on roads with a range out to 500 kilometers. Like the BT series of tanks, the TG-1 could also be run track-less on its roadwheels, improving driving ranges out to 700 km on prepared roads. The tank could ford water sources up to 1.2 meters deep.
Soviet authorities believed enough in the tank to plan for a fleet of 2,000. This was quickly undone when it was revealed that about twenty-five BT-2 Fast Tanks could be hand for the price of a single TG-1 - thus ending the TG-1 venture.