Assembling the first ten series T -26 the so-called adjusting party with
the housings of [nebronevoy] steel was completed in the summer of 1931
at the Leningrad plant “Bolshevik”
I would probably translate to:
Assembling the first ten vehicles of the T-26 type vehicles the manufacturing team with
the basic structure shell of steel for armoured vehicles was completed in the summer of 1931
at the Leningrad plant “Bolshevik”.
Note for early car design you had a chassis made of strong materials like steel that you attach things to like the engine and transmission, plus the shell of the car body etc. With armoured vehicles the armour is like the chassis... it is the structure that the wheels and engine and turret etc are attached to.
With many modern cars the car shell is the structure and things are attached to it. This makes possible crumple zones to reduce the effect of an impact on the passengers and driver. Light trucks still use a heavy chassis, as do most 4WD and SUV type vehicles as that allows them to handle rough cross country use.
In its course they introduced undertower box with the inclined armored
plates, on the part of the tanks they withdrew stern machine gun, and
instead of it was installed additional ammunition stowage to 32
projectiles.
A design change was a box under the turret with angled armour plates. They removed a rear mounted machine gun (from the back of the turret) and instead of that machine gun they stored an additional 32 rounds of main gun ammo in the space freed up. The machine gun was likely a DT model, and the extra ammo would be 37mm.
Furthermore, machine they supplied with the standardized inspection
instrument, the new pursuit of tower, they introduced Bakelite coating
fuel tanks.
They standardised the vision periscopes to see outside of the vehicle, added straps to the turret {presumably to carry more kit}, and introduced Bakelite coating to the fuel tanks.
Note the purpose of the Bakelite coating is to improve the protection of the fuel tanks in combat. Bakelite will not stop a bullet but a bullet penetrating a fuel tank with Bakelite lining, when the Bakelite is exposed to outside air it hardens and would reseal any hole in the fuel tank. This prevents fuel leaking all over the place, which is a fire risk and it also reduces the chance of an explosion within the tank by preventing air getting in... which is needed for a fire or explosion.
On the eve of the Second World War T -26 they were in service mainly of
individual [legkotankovykh] brigades (256-267 armored machines in each)
and separate tank battalions of rifle divisions (one company, 10-15
machines).
They were used mainly in large (256-267 vehicles) unwieldy formations of light tanks, or in small groups (10-15 machines) attached to rifle divisions as infantry support vehicles.
Note most did not have radios and responded either to signal flags... or simply followed the vehicle in front of them.
The park T -26, which was being used during “winter” campaign, was very
[pestrym].[V] brigades, which was armed with combat vehicles of this
type, were encountered the two-tower, and [odnobashennye] tanks of the
different years of release (from 1931 until 1939).
The available in service T-26s used during the winter war in Finland were of a variety of versions within brigades, and included obsolete twin turret early models and other obsolete tanks from 1931 to 1939.
Note the twin turret models they mention is an early model with two turrets each mounting a machine gun, which by 1939 was obsolete. What they are basically saying is that they took the T-26 into combat in Finland but that the T-26s they took ranged from obsolete to inadequate as even the latest models with 45mm guns were found to be vulnerable to anti tank weapons of the day.
My translations come from Babel Fish at http://babelfish.yahoo.com and a bit of educated guess work.
If anyone with a better understanding of Russian has any corrections please speak up...
(I neither speak nor can read Russian so there are likely some mistakes...)