In a rather weird way, H.G. Wells wrote about the possible future of tanks and pessimistically envisioned monstrous battleship sized machines capable of carrying huge batteries of guns and plowing the landscape before them due to the immense weight.
What lies behind the Tank depends upon this fact; there is no definable upward limit of mass. Upon that I would lay all the stress possible, because everything turns upon that.
You cannot make a land ironclad so big and heavy but that you cannot make a caterpillar track wide enough and strong enough to carry it forward. Tanks are quite possible that will carry twenty-inch or twenty-five inch guns, besides minor armament. Such Tanks may be undesirable; the production may exceed the industrial resources of any empire to produce; but there is no inherent impossibility in such things. There are not even the same limitations as to draught and docking accommodation that sets bounds to the size of battleships. It follows, therefore, as a necessary deduction that if the world's affairs are so left at the end of the war that the race of armaments continues, that Tank will develop steadily into a tremendous instrument of warfare, driven by engines of scores of thousands of horse-power, tracking on a track scores of hundreds of yards wide and weighing hundreds or thousands of tons. Nothing but a world agreement not to do so can prevent this logical development of the land ironclad. Such a structure will make wheel-ruts scores of feet deep; it will plough up, devastate and destroy the country it passes over altogether.
Illustration from 1939
Of course, being a "linear projection", it takes a basic idea and inflates it to rather absurd dimensions. Wells was no crank, however. He had actually predicted armoured fighting vehicles in a 1903 story "The Land Ironclads" (technically, the Tripods from the War of the Worlds were also AFV's), and was an enthusiastic supporter of the development of real tanks when they were developed by the British.
A Land Ironclad
And this trope has carried on in Science Fiction and games with ideas like "Bolo" AI driven tanks and the Ogre war-game.
However, once you re read the description of the Wellsian super tank, you see the issues. Engines with "scores of thousands of horsepower" are absurdly huge (especially with 1930 era technology) regardless of what your power source is. The bulk of the machine will be made up of engine bays and transmissions. Since the engines will not convert 100% of your energy into motion, you need some sort of radiating mechanism. A ship at sea can dump its heat into the ocean, but on land it becomes a bit more difficult. You might be looking at a cooling system similar in size to the massive cooling towers at a nuclear power station.
The next issue is the mechanical strength of the chassis. A ship is fully supported by the water it displaces, but your vehicle will have hundreds or thousands of separate stress points in the suspension and track system. The body will be similar to a bridge standing on pylons, so there will be sections cantilevered between suspension elements. The body will be subject to stresses in multiple directions since the ground isn't flat, and firing stresses will complicate matters even more. When you consider a modern torpedo kills a ship by exploding under the keel and creating a cavitation bubble, snapping the ship where it is no longer supported, then consider the same effect will occur when the vehicle will be subject to similar stresses when crossing a stream, valley or even sufficiently large ditch.
Finally, this thing will be a target. It will be moving slowly enough that everything from long range artillery and bomber aircraft to tank hunting teams with explosive charges will be assembled and sent into action long before this thing can get into range of its target. Your multi million dollar investment will be smoking ruins, quite possibly before you even hit the beach (the Captains of the HMS Prince of Wales, IJN Yamato and the Bismarck can explain this more fully).
Given the parameters that you provided in the setup, it would be far more plausible for the attack to be made by carrier born bombers or even large seaplanes than to expend the time and energy needed to create the monstrosity you are describing.