The terraforming engines would have been built by the initial Adamantine team, long before the colonists arrived. The individual parts would be sort of like a transport module, with each one capable of subspace propulsion. They had been towed here through the wormhole, then released into the system where they would have flown the rest of the way to the planet and landed under their own power. Traveling with the engine modules would be a human and bot crew that specialized in terraforming assembly and installation, who would have connected everything up and gotten it started. At least, that’s what the Adamantine brochure I’d downloaded from the drop box control station had said.