To get an opponent for the german Maus I bought this:
"The T28 was a superheavy tank design by the United States which started the development in 1945 for the final push in Europe attacking the heavy tanks and fortifications.
A 105mm cannon was built into a fixed superstructure on a T23 base. The armor plates were up 300m thick which gave the tank a weight of 86.2 tons. To carry this weight on soft ground, two additional tracks were installed doubling the track width. Theses outer track compartments were detachable and could be put behind the tank for transport. The engine delivered only 500hp which gave that tank a maximum speed of 13 km/h.
Only two prototypes were built and tested throughout 1947 at Aberdeen Proving Grounds as well as at the Fort Knox facilities. In October 1947 the T28 program was cancelled and it never went into series production"
Cheers Kalle