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

The Bulldozer is an utility land vehicle designed to terraforming and ground clearing tasks. Like the harverster, when its blades (iron bars) comes into contact with soil and loose blocks, it breakes them, with the items being dropped into 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 wouldn't be stored), tree leaves, logs and, maybe, all wooden blocks. Bulldozers cannot break stone blocks.

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

Because of it's nature, Bulldozers will have a cruising speed around 5 m/s. Not only because of this aspect but in order to let the craft move one block each cruising (like the harvester). This way, the pilot can just sit and leave the machine do it's work without having to use stick movement.