Bulldozer concept: https://imgur.com/a/ORBkrqY

The Bulldozer is a utility land vehicle designed for terraforming and ground-clearing tasks. Like the Harvester, when its blades (iron bars) come into contact with soil and loose blocks, it automatically breaks them, dropping the items onto the ground.

A list of blocks that can be destroyed using the bulldozer would be: grass, dirt, sand, podzol, mud, all plants and flowers, crops (they won't be stored), tree leaves, all snow layers, logs and, maybe, all wooden blocks. Bulldozers cannot break stone blocks.

Its specifications would be similar to those of the Truck: 100 to 600 blocks, at least 30% of concrete, 5% of redstone blocks and 3-5% blast furnace blocks, given the fact that it's a heavy-duty machine like the Train.

The operation of such powerful machine would require a significant amount of fuel, ensuring that it won't make it too easy to deface the map. A fuel consumption rate 20-25% higher than the Truck would be appropriate.

Because of its nature, Bulldozers would have a slow cruising speed around 4 m/s, moving one block each cruising (just like the harvester). This way, the pilot can just sit and leave the machine do its work without the need of stick movement.