T-54/T-55 Upgrades
In its long service life the T-55 has been upgraded many times.
Early T-55s were fitted with a new TSh-2B-32P sight. In 1959, some tanks received mountings for the PT-55 mineclearing system or the BTU/BTU-55 plough. In 1967, the improved BM8 APDS round, which could penetrate 275 mm thick armour at a range of 2 km, was introduced. In 1970, new and old T-55 tanks had the loader's hatch modified to mount the 12.7 mm DShK machine gun, to deal with the threat of attack helicopters. Starting in 1974, T-55 tanks received the KTD-1 or KTD-2 laser rangefinder in an armoured box over the mantlet of the main gun, as well as the R-123 or R-123M radio set. Simultaneously efforts were made to modernize and increase the lifespan of the drive train.
During production the T-55A was frequently modernized. In 1965 a new track was introduced which could be used for between 2000 km and 3000 km which was two times more when compared to the old track. It required a new drive sprocket with 14 teeth instead of 13. Since 1974 T-55A tanks were equipped with a KTD-1 "Newa" rangefinder and TSzS-32PM sight. All T-55A tanks were equipped with the TPN-1-22-11 night sight. The R-113 radio set was replaced by a R-123 radio set. Late production models had rubber sideskirts and a driver's windshield for use during longer stints.
T-54 and T-55 tanks continued to be upgraded, refitted, and modernized into the 1990s. Advances in armour-piercing and HEAT ammunition would improve the gun's antitank capabilities in the 1960s and 1980s.
A wide array of upgrades in different price ranges are provided by many manufacturers in different countries, intended to bring the T-54/55 up to the capabilities of newer MBTs, at a lower cost. Upgrades include new engines, explosive reactive armour, new main armament such as 120 mm or 125 mm guns, active protection systems, and fire control systems with range-finders or thermal sights. These improvements make it a potent main battle tank (MBT) for the low-end budget, even to this day.
One of these upgrade packages was produced by Cadillac Gage Textron and a prototype named the Jaguar was produced. The Jaguar looked quite different from its predecessors. A newly designed turret was formed by flat armour plates installed at different angles. The hull top was new. The engine compartment and fuel tanks on the shelves over the tracks were armour-protected. The Soviet-made 100 mm gun was replaced with the American M68 105 mm rifled gun fitted with a thermal sleeve. A Marconi fire control system which was originally developed for the American light tank Stingray was fitted. The vehicle incorporated a Cadillac-Gage weapon stabilizer and gunner's sight equipped with an integral laser rangefinder. The powerpack inherited by the Jaguar from the Stinger underwent only minor alterations and comprised the Detroit Diesel 8V-92TA engine and XTG-411 automatic transmission. In 1989, two Jaguar tanks were manufactured. The chassis were provided by PRC, while the hull tops, turrets and powerplants were manufactured by Cadillac Gage Textron.
Another prototype upgrade package was produced by Teledyne Continental Motors (now General Dynamics Land Systems) for the Egyptian Army and was known as the T-54E. After further modifications and trials it was sent into mass production and received the designation Ramses II.
Read more about this topic: T-54/55, Development History