Ukraine has been upgrading Cold War era Russian tanks a lot since it became independent from the Soviet Union in 1991. Those upgrades became more urgent and imaginative after late 2014 when Russia began trying to seize a lot of Ukrainian territory. By the end of 2015 the Ukrainians improvised and stalemated the surprised Russians. The improvising has not stopped and in 2016 Ukraine began work on a T-64 upgrade that would be competitive (and a lot cheaper) than the new Russian T-14 tank that was first shown in public in 2015.
The Ukrainian T-Rex uses the chassis of T-64s but has been extensively modified to include a heavily armored capsule for the for the three man crew. Extensive use of vidcams and other sensors gives those in the crew capsule constant coverage of whatever is going on outside the tank from all directions. Weapons are remotely controlled from the capsule. These include a 125mm gun with a proven autoloader system plus a RWS (remote weapons station) with 12.7mm machine-gun on top of the turret. The 40 ton T-Rex is certainly a budget T-14 and is supposed to be ready for testing by early 2018.
Meanwhile the T-14 already exists and is the first major innovation in tank design since World War II. Russia has been trying to develop a radical new tank design since the 1960s. That resulted in the T-64, T-72 and T-80. The only design that survived all the hype was the T-72, but it was not radically new, just a refinement of designs (especially the T-34) that appeared early in World War II and quickly replaced all competing designs and became the basis for all modern tanks (T-72, M-1, Leopard and so on). When it was clear (by the 1980s) that the T-72 was the best they had, several new versions appeared, not all of them Russian. But it was obvious (especially after several wars) that the T-72 was inferior to Western designs. Russia needed something radically new that worked. Sort of a T-34 for the 21st century.
Russia sought to create another breakthrough design and after several false starts they believe they finally have a winner in their new “universal combat platform” called the Armata system. The first prototypes of this vehicle began testing in 2013 and the Armata platform is currently being used for the construction of the new T-14 tank prototypes. This vehicle uses the engine and tracks as well as the heavily armored crew capsule of the Armata system. Added to this is an automated 125mm gun (and 32 shells and missiles) in a turret. There is also a RWS for a 30mm autocannon and another for a 12.7mm machine-gun. In addition to the weapons the crew of three would operate several sensor systems (thermal, vidcams and AESA radar) and an automatic defense system for protection against missiles and weapons like RPGs (shaped charge rockets used by the infantry). The three man crew operates all these systems from a heavily armored capsule. There is no one in the turret. All this is in a 55 ton vehicle that requires the services of additional maintenance personnel nearby (behind the fighting) who would help fix problems and assist the crew in maintaining all this complex equipment. Prototypes of the T-14 were available for field testing in 2015. It was one of these prototypes would make a public appearance at the late 2015 Victory Day parade. So far about two dozen prototypes have been built for testing. In late 2016 the government ordered a hundred pre-production models of the T-14 for more extensive field testing. The original plan was to begin mass production by 2020 but that has been pushed to 2025 because of money shortages (T-14s cost $4 million each) and technical problems (known and expected). Another limitation is that current manufacturing facilities can only produce about 1,500 T-14s a year. Thus it would take a while to replace the 2,000 tanks required by the active duty forces. At the end of 2016 Russia announced it would not wait and instead will upgrade some of the 3,000 T-80U tanks they have in reserve. The army would prefer the more expensive T-90s or T-14s. But new tanks cannot be built fast enough. Russia currently has about 500 T-80Us in service and in 2002 planned to upgrade more than 2,000 of them. Now, faced with reduced defense budget and an untested new design (the T-14) it was decided to upgrade more old T-80Us because as upgraded these appear to be about as capable as the T-90 and a lot cheaper.
The Ukrainian T-Rex may appear hopelessly ambitious but since 2014 the Ukrainians have performed seemingly impossible feats of improvisation with refurbished and modified tanks. In an effort to deal with the need for modern military equipment to fight the Russian-backed rebels, the Ukrainian government is focusing on its local resources to rebuild its armed forces. This is a necessity because most Western countries refuse to supply Ukraine with weapons because Western leaders believe it would not help Ukraine on the battlefield and would simply escalate the conflict. Ukraine disagrees and in order to maintain a credible defense against the Russian backed rebels (which often include Russian troops) Ukraine is rearming itself with local resources. Despite the vigorous European and American rhetoric, this support has mostly diplomatic and economic. Foreign attempts to assist in modernizing the Ukrainian armed forces have been token gestures.
Ukraine needs new and improved armor vehicles. In response Ukraine is refurbishing existing equipment with Ukrainian resources. Emphasis is on armored vehicles, which Ukraine has lots of. Most are elderly but were little used in the past and still effective. The best tanks available to Ukraine right now are 250 T-64BMs and 350 T-64BVs. Ukraine also has 1,000 older T-64B tanks in storage. Only the T-64BM and T-64BM are operational and are in use with the Ukrainian Army. The Since 2007 Ukraine has been upgrading about one of the older T-64Bs to the T-64BM each month. This costs about $600,000 per T-64B. Ukrainian arms factories are also building the T-84 Oplot-M tank and 55 were in service by the end of 2015 and 120 more in 2016 at a cost of $3.7 million each. All this is possible because Ukraine contained many Soviet era armored vehicle plants and inherited them when the Soviet Union dissolved in 1991.
Ukraine also began upgrading about 300 T-72B tanks held in reserve. These will become similar to the Polish PT-91. The official reason for this is that Ukraine wants the T-72Bs to meet NATO requirements but the upgraded tanks would also improve the defensive capabilities of the Ukrainian Army forces fighting in eastern Ukraine. The upgrade idea came as a result of Ukrainian military officials being given an opportunity to test some PT-91s.
Such cooperation between Poland and Ukraine is nothing new because since 2011 defense firms in the two countries have worked together to develop guided 155mm artillery and 120mm mortar shells. Another cooperative effort enabled a Polish firm to develop a less expensive alternative to the Israeli SPIKE ATGM (Anti-Tank Guided Missile) that was based on the Ukrainian RK-3 Corsair ATGM. Ukraine, like Russia, has little choice but to refurbish older vehicles and hope for the best.