T-26 Model 1936 Light Infantry Tank
In 1934-35, fighting broke out in the borderlands between Manchuria and Mongolia with Japanese forces, and Soviet tank units took part.
Some T-26s were involved in the fighting and alarming reports were sent back, critical of the use of rivets in tanks.
It was found that rivets came free when struck on the outside by bullets, causing the inner face of the rivet to careen about the inside of the tank, often with lethal results.
The problem was so serious that Tukhachevskiy himself ordered the production lines closed down temporarily until the problem could be resolved.
As a result, Soviet tank designs began to drop the use of riveting in favour of welding and the production batches from 1935 on gradually showed more and more welding from the hull to the turret.
Additonal changes and improvements included :
- fully traversable circular roof hatch with P-40 machine-gun mount for use against aircraft (1937),
- two turret combat lights for night fighting (on every fifth vehicle),
- additional 7.62mm DT machine gun ball-mounted into turret rear (1936),
- improved optical sights and PTK periscope,
- extra armour front plate to driver compartment,
- front light protection box and different horn location,
- increased fuel capacity doubling the fighting range,
- new road wheels with larger steel rim,
- new-style jack and spare springs instead of spare roadwheels.
In total, almost 600 units were produced at plant N° 174 im. K.E.Voroshilov in Leningrad.