We had a Cleveland machine years ago that we used to run water line, depending on the soil, depth, it moved at a fast pace, there are a lot of moving parts that take grease and service along with adjustments. The nice thing is when the material is good it makes backfilling better with less large chunks of material. Most had a fixed width, seem like ours had a 20" cut for the 8" water line. You have to have a backfill machine, and they are heavy, ours had crane pads, slick and would not pull well on wet ground. Their is a nice one on govdeals that would make someone a good machine. The trackhoe can do it all, dig, backfill, load material, get thru wet spots, etc. Most use a pull plow and crawler/large 4wd tractor. Sometimes you can contract it done cheaper depending on the acres involved.