Staff Writer (Updated: 4/5/2016):
Before the arrival of the T-35 was the inception of the T-28 Medium Tank, a design appearing in 1922 and sporting a top speed of 22 miles per hour, weight nearing 29 tons and featuring a multi-turret design (this approach also proving somewhat popular with other nations in the 1920s). A plodding vehicle she was, the type was adequately armored and projected good firepower for the time. Some were fielded by Soviet forces during the Spanish Civil War and in the upcoming Russo-Finnish War though their tactical limitations ultimately began to show through. Her inherent deficiencies copled with poor Soviet battlefield deployment negated any tactical usefulness in combat. Regardless, the type served as a design direction for a subsequent heavy tank design - the new T-35.
At its core, the T-35 was intended to work in conjunction with existing T-28 tanks. The basic idea - building upon accepted armored warfare doctrine emerging in the 1920s - was to utilize the heavier T-35 as an offensive frontline "breakthrough" vehicle that could breach fortified enemy positions and defenses for which then the T-28 could move in to exploit these created gaps. The heavy tank's main gun could help tackle enemy armor while smaller caliber cannons could deal with light-armored vehicles and troop concentrations, leaving machine guns to counter aggressive infantry attempting to storm the tank from vulnerable angles at short range. However, warfare has changed by the 1930s and this type of armored warfare was, in many ways, made obsolete by new technology and doctrine - the German invasion of the Soviet Union through Operation Barbarossa in the summer of 1941 would certainly drive the point home for Soviet tank engineers.
Design work for a new heavy-class tank began in 1930, brought about by a series of design studies and apparently stemming from a Soviet interest in the 1925 British Vickers A1E1 "Independent" tank project - a "one-off" heavy tank prototype fitting multiple turrets. The resulting initiative produced the "T-32 Heavy Assault Tank" of 1932, a similar multi-turret creation weighing 45 tons with a 17 mile per hour road speed. Mechanical issues with its hydraulic transmission system ultimately doomed the T-32 and forced work on a simpler concept - the "T-35". The T-35 borrowed some of the T-32 design elements including its multiple turret layout. The new vehicle was then evaluated and formally accepted into serial production for Red Army service in August of 1933. Initial production was out of the Kharkov Locomotive Factory to which some 20 first batch vehicles were delivered. Production proved a timely affair for each T-35 system was an inherently complex machine to piece together and proved quite costly in the long run to the point that only 61 total vehicles - each production batch with slight differences - were completed. Production ended in 1939. The final six machines featured sloped armor, revised skirts and new track idlers.
The T-35 was initially delivered to only a single tank brigade - the 5th Independent Heavy Tank Brigade - outside of Moscow and did little more than serve as a parade showpiece than a full-fledged combat tank. In that respect, the T-35s really were nothing more than centerpieces of the proposed Soviet tank strength but provided something of a false symbol for their capabilities were lacking when compared to the German tanks they would ultimately be facing.
In 1941, the Soviets were reeling from the German invasion to open up the East Front and any war-making instrument of value was sent to fight. However, many T-35s were subject to mechanical failure (transmission, engine, brakes clutch or otherwise) and fuel shortages while even en route to combat and were seemingly out of action before they arrived to the fight - crews simply abandoning their mounts in the streets. German crews then either took these examples over or destroyed them where they stood while a few small numbers were actually lost in direct confrontations. Most available T-35s were stationed in and around Moscow for security duties and defense of the capital, limiting their combat reach.