The M-28 Heavy Tank was an old heavy tank still used by American forces in the Sino-American war.
The M-28 Heavy tank was a complete upgrade and re-design of the M-26 Pershing from WWII, made in 2046. When the Army realized they needed to fill a niche a MBT (Main Battle Tank) could not, they created the M-28. The M-28 is designed for infantry, and fire support, while other tanks were designed for armored warfare. The M-28 boasted a massive 152mm rifled cannon, almost the same size as standard seige artillery. It also featured the newly designed (at the time) American "Chobham" armor, that would later become stadard for most American MBT's and medium tanks. The tank was originally by a diesel engine, but because of oil shortages, it was changed to a hybrid plasma engine. Its top speed is 45mph which was outstanding for a heavy tank, it also gave it advantages over Chinese tanks.
During the Sino-American war, the M-28 was used to its full potential, destroying bunkers, being used as make shift artillery, and protecting infantry from Chinese Type 51 Bulk tanks, the standard of the PLA. While not designed for tank to tank warfare, the M-28's proved themselves as combat able as the higher tech M-56 and M-75 MBTs. The M-28 also holds the honor of the only tank to ever defeat an M-56 MBT in tank to tank combat. On that ocasion, Chinese tank crews hijacked a previously disabled M-56 and began using it to desimate an American armored collem. The two M-28's of that collem opened fire with ATPP (Anti Tank Plasma Penetrator) rounds. These rounds were very powerful, capable of destroying even Soviet T-87 tanks. However the two M-28s had to fire over 15 rounds a piece just to destroy the M-56. But the venerable M-56 finally gave in, when the second M-28 "Molly" scored a direct hit just under the turret. This caused a tear in the armor, which was exploited by infantry forces with "Fat Man" units. 2 fat man teams fired 4 warheads a peice at the M56. The Chinese crew inside were killed from the burns and radiation.
On October 23rd, 2077 when the world was consumed in nuclear fire, the over 8,000 M-28's in asia were all but destroyed by Chinese and American nuclear weapons. Only around 60 survived, the tanks now in possession of the U.S. Military remnant.