Note: Many thanks to Wargaming's Cannoneer. Whom found several Russian sources on this subject, when English language sources failed me. Consequently I've had to translate the sources, and any errors are down to Google translate playing word soup with the source material.

In 1920, the Czech writer, Karel Čapek published a play that mentioned a new concept, that of the "Robot". Little did he know less than a decade later one of the worlds armies would be developing a robot tank. These robots actually saw combat in the opening days of the Second World War. Today we shall look at their brief combat history.
In February 1930 the first of a series of tanks that became known as "Teletanks" was tested. The remote control equipment was fitted to a Soviet MS-1. However the high center of gravity meant that the tank would often veer off to one-side. Most Soviet tracked armoured vehicles were tested as Teletanks, eventually the T-26 was selected.
The idea behind the Teletanks was that the remote controlled tank would advance on the enemy lines, and lead the assault, but not risk the crew to enemy fire. The name Teletanks implies some kind of remote monitoring by Television cameras, indeed the first experiments tried this. However Technology at the time was too limited, so the Camera's were dropped from the design. By the early 30's the basic system was decided. A box of 20 buttons, in five rows of four was mounted inside a T-26 tank. These were the command tanks, designated as TU-26's. The remote control tanks were TT-26's.

The boxes would send a radio signal to the TT-26 each time the button was pressed, each button corresponded to a set command. When the radio antenna, located behind bullet proof glass, on the TT-26 received a command it would cause a compressor to fill a balloon with air. Which in turn would move a lever, and so a series of simple pistons would carry out the command.
Due to the tank only being able to operate within visual range of the TU-26, weapon sighting was considered. As the aiming had to be done from a distance, the weapons fitted to the tank were a machine gun and a flame-thrower. The projector could also fire out liquid chemical weapons should it be needed. A smoke generator was also fitted, to provide cover for advances. Finally as a safety feature the TT-26 would automatically shut-down if it went out of radio control range.

The TU-26 command tank was a normal T-26 tank, only with the additional control equipment fitted. So as well as controlling the Robot, the command tank could cover it with its 45mm gun. To protect the secret nature of the tank the command tank could destroy the TT-26 should it become damaged or be in danger of getting captured.

Teletanks were produced for three years from 1935 at factory 174 based in Leningrad. During that time only 33 sets (one TT-26 and one TU-26) were completed. Those tanks were formed into two battalions and an independent company. These were the 152nd and 217th Separate Chemical Tank Battalions. The 152nd took part in the Western Ukrainian campaign of September 1939, but was never used. Later it was stationed near Rovno, where it was bombed by the Germans during Operation Barbarossa.

During December 1939 the Soviets launched an attack on Finland. At Hill 65.5 the Russians ran into Bunker SJ-4, also known as Fort Poppiusa. Part of the Mannerheim line the fort was a complex of bunkers overlooking a valley, at one end of the valley the ground became very boggy, at the other was a lake. In this valley in a five day assault over 1800 Soviet soldiers were killed, and the Red Army soldiers began to call it the Valley of Death.

On December 17th the Teletanks were to be used as designed for the first time. The 1st company with three TT-26's was to scout the Finish position. Hoping to draw enemy fire and give away the Finish positions so they could be targeted. The tanks crunched across the thick snow towards the enemy hill. However that snow also camouflaged and covered a line of dragons teeth. All three TT-26's became beached upon the obstacles. Unable to move the Tanks opened fire with both flame-throwers and machine guns, hoping to goad the defenders into giving their locations away. The Finns failed to take the bait. That evening two of the TT-26's were recovered, the other one was stuck fast and couldn't be recovered.
Elsewhere along the line five Teletanks were deployed to support an assault by Russian infantry. Here the snow cover was much thicker and the Teletanks managed to drive over the dragons teeth. However all five were quickly, and easily destroyed by Finish Anti-tank guns.
On the 10th of February 1940 a new plan was hatched. Three TT-26's were stripped of their turrets and weapons, and filled with as much explosive as could be packed in. Each tank now carried well over two tons of explosives, these tanks were named simply "bombs". Near Hottin lay a large concrete bunker. The three "Bombs" were directed towards it. The Finns saw the approaching tanks and opened fire. Again he poor armour of the T-26 failed, one of the "bombs" was hit and penetrated. A colossal explosion tore the tank apart and disabled the other two.
The final taste of combat for the Robots was between February the 14th and 18th. During this period the tanks were used to try and destroy Finish minefields, presumably with their flame-throwers. Four TT-26's were lost to hitting mines.

Earlier in February the OKMO plant in Leningrad, had unveiled the next generation of Teletanks. It was an officially produced "bomb". The armour had been reinforced with an additional 50mm, and it had a detachable container with a 700Kg explosive charge. The first of these arrived in Finland on the 28th of February, even so it didn't see service. It was tested against Finish bunkers after the Soviet breakthrough. In one test the charge blasted apart five of the sturdy dragons teeth. In the next test against Fort Poppiusa, the charge destroyed the bunker.

The story of the 217th Battalion isn't quite over yet. As the Germans approached Moscow in late 1941, the battalion had been brought back up to full strength. There was no need for remote controlled tanks for attacking heavily defended lines in the new Blitzkrieg war. So the special equipment was replaced by 45mm guns, and the tanks manned with crews. The TT-26's fought their last battle as normal T-26 tanks defending the Russian capital.