A Bolo is a fictional type of artificially intelligent superheavy tank. They were first imagined by Keith Laumer, and have since been featured in science fiction novels and short story anthologies by him and others.
During WWII the bane of the 30 metric ton Sherman with 75 mm gun was the much larger German Tiger tank of 50 metric tons with 88mm gun. The Tiger II's were even heavier at 60 metric tons. However, Germany's largest tank was the Maus which weighed 192 metric tons. It is in this design that we can see the possible inspiration for Laumer's Bolo vehicle. The Maus was not only 3x the weight of a Tiger II but used a turret holding a 128mmKwK44(as in the Jagdtiger) and a special designed 75mm KWK44 side by side or co-axial. As typical for Porsche designs (the Leopard I is an exception) the Maus also used a complex but potentially high-torque/low revolution diesel/electric drive (See also Elephant) instead of the simpler transmission and clutch used on tanks and bulldozers.
In a very large tank such as the Maus we can also see why the sloping frontal armor would be reminiscent of the glacis protecting the walls from battering rams on medieval fortresses. One could extrapolate from the Maus to a vehicle about 5x heavier and arrive at a Bolo which even at 1,000 metric tons would still be less than 1/10th the weight of the 13,600 metric ton tracked power shovel, The Captain which was completed in 1965.
The unusual dual track design seems to be shared with the US T 28 superheavy tank (also known as T95) an assault-gun style bunker buster prototype build in late WWII. .
Read more about Bolos (supertanks) at Wikipedia ...
Official Site: Keith Laumer
Links: Bolo Wiki entry William H. Keith's Bolo site Bolo Mk. XXXIV Schematics