on wheels

"That prosecutor seems like a real bitch on wheels," Amanda says […] .

The order was written. In less than ten days everything was "on wheels" and the whole body of these Sioux [was] on the move to the country they had indicated, and the Secretary of the Interior says, naively, in his report for 1868, "The Indians were found to be quite determined to move westward, and the promise of the government in that respect was faithfully kept."