In the early 1930s, the Soviets took to designing an indigenous tank - specifically the T-28 Medium Tank series - based on lessons learned British and German experimental designs. The ultimate goal was to produce an in-house tank of modern standards that fit soundly within Red Army mechanized doctrine of the time. As such, the design of the T-28 was something of a throwback to post-World War 1 style ideas featuring long running side-mounted tracks, a slab-sided superstructure integrated to the hull and multiple turrets housing various caliber armament. The main armament (housing the largest caliber weapon) would be conventionally set within a 360-degree traversing rounded turret at the middle-forward portion of the superstructure while lesser-caliber offerings were given a pair of individual - albeit smaller - rounded turrets, these flanking the main gun but with a limited field of fire. The driver would be positioned in the forward hull, himself being flanked by the smaller pair of turrets. The vehicle would be crewed by no less than six personnel to man the various systems. The general idea behind such a seemingly complex arrangement lay in the fact that the tank system could bring fire to bear from a variety of angles and concentrate its firepower against any one target as required. Additionally, the Soviets held little in the way of in-house knowledge of tank designing to break from anything other than the norm so this methodology proved the call of the day. The new tank, as it was, would be something of a learning experience for the nation itself. While appearing as an archaic attempt by any regard, the new design would go on to serve Soviet tank engineers with valuable information to apply to future tank endeavors for the upcoming World War 2.
A pilot (prototype) vehicle was completed and Soviet engineers initially fitted a 47mm caliber main gun to the primary turret. For the time this would have been sufficient but soon outmoded by the new breed of tanks soon to appear in upcoming wars. Realizing this, engineers revised the production model - designated as T-28 (Model 1934) - to house a more powerful, short-barreled 76.2mm main gun. A similar follow-up production model was known under the designation of T-28A and given more armor protection. Production of this first series came out of Leningrad factories in 1933 and lasted until 1938 to which a revised design soon came online as the T-28B (Model 1938), this by the end of the year. The variant was "upgunned" with a long-barreled L-10 series 76.2mm gun and given a basic stabilization system for more accurized fire. The engine line was revised to improve performance and help bring the T-28 up to capable levels in the changing world. Production of the T-28B lasted until 1940. However, large antiquated beasts such as the T-28 would have run their course by now and production ceased only to allow newer and more modern tank systems to take her place. Some 503 T-28 tanks were ultimately produced.
Despite weighing in at an impressive 30 tons, the T-28 was in fact classified as a medium tank. Armament centered around her 76.2mm armament, a caliber which proved relatively effective and became something of a Soviet Army norm through to the end of the war. The main gun began as a short barrel form and graduate to a more effective long-barrel design. Self-defense was held by 7.62mm single-mounted machine guns held within two smaller turrets. The main turret, housing the main gun, was also home to a rear-facing machine gun to help protect the tank's rear from infantry grenade attacks. The Soviets generally fielded such a defensive armament in most of their World War 2 era tank designs to protect the critical engine compartment - always held at the rear of a tank. Up to 70 projectiles of 76.2mm ammunition were carried aboard. Each track side was covered over in side armor skirting emanating from under the four track return rollers. There were no fewer than twelve road wheels per track side, these held in pairs and suspended by plunger springs. The drive sprocket was at the rear with the engine while the idler was fitted to the front. Power was derived from a single Mikulin M-17 series 12-cylinder engine generating 500 horsepower. Speed was up to 23 miles per hour with an operational range out to 140 miles. Armor, at its thickest, ran in the neighborhood of 30mm.
Like any other sound tank system, the T-28 chassis was utilized in a variety of "spin-off" projects to extend the usefulness of the inherent base system. Evaluation was undertaken to test the validity of the T-28 as a self-propelled gun, an engineering vehicle and a bridgelaying (IT-28) instrument of war. A prototype "T-29" was developed to showcase the T-28 design utilizing a Christie suspension system. However, all of these projects - while some having reached prototype forms - fell to naught in terms of serial production efforts. Despite these failed attempts, Soviet tank engineers once again garnered much valuable experience in these forays.
The T-28 was outmoded and outclassed by the time World War 2 was in full swing. As such, she led quite a short operational military life for the Red Army - probably a good thing considering her inherent limited qualities when compared to her contemporaries. Her actual combat record spanned a short window from 1939 to 1941 and Red Army tank crews assigned to T-28 units saw combat in the "Winter War" during the Soviet invasion of Finland.
However, the T-28 shown her limitations in the limited war particularly in the department of armor protection. For the series as a whole, the T-28 sported armor thickness ranging from 0.79 inches up to 3.15 inches and, against the anti-armor weapons and specialized tactics of the Finns, the T-28 suffered mightily. Such was the failure of armor protection that in-the-field modifications (known as applique armor) were undertaken to supply T-28 crews with a fighting chance, bringing armor protection in parts up to as much as 6 inches. T-28 tanks modified as such came under the added designation of "T-28E" to signify their changes: "E" for "ekanirovki" translating to "screened" but moreso carrying the meaning that they had been "uparmored". The T-26E also fell into the Soviet Army inventory under the designation of T-28C or T-28M (Model 1940). Further attempts to extend the usefulness of the T-28 in the Finnish War led to some hulls being fitted with mine rollers in an effort to spot and activate enemy land mines before the "softer" undersides of advancing T-28s were exposed to them. This action undoubtedly would have tested the nerve of any tank crew.
By the time of the German invasion of the Soviet Union in 1941, the T-28 had seen her best days behind her. The armor upgrade program was suspect at best and the T-28 was slow, plodding and the multiple turret systems with the multiple weapon systems proved cumbersome to try and coordinate in the heat of battle. The type of 76.2mm gun fielded by the T-28 was regarded as inadequate against new German armor developments. The slab-sided armor of the T-28 herself made for a tempting target to anti-tank crews and proved easy to penetrate by shaped projectiles at distance. Performance qualities of the T-28 degraded with the addition of the extra armor and crews were essentially sitting ducks if caught out in the open by German tanks. In the moment, the T-28 was finished as a combat tank, ready to be replaced by the products of experienced Soviet tank engineering that would bring about such war-winning designs as the KV and IS heavy series as well as the world renowned T-34 medium tank.
Beyond Soviet Army use, the T-28 found its way (in limited numbers) into the inventories of Finland, Hungary and the German Army as captured spoils of war. It is believed that Turkey purchased a pair of T-28s outright in 1935 as part of a broader military vehicle purchase. Spain may have received a single T-28 example from the Soviet Union during the Spanish Civil War of 1936-1939, the war proving essentially a testbed for new and exotic military machines.