I saw an excavator last week working in a road. Forgot the brand but was probably about the size of a PC-300. What was interesting was it had some type of conveyor going under it. Anyone ever see one? I'm guessing it's for backfilling the trench?
It's a bedding hopper. A loader will fill it (the hopper is in the rear), and the excavtor operator can run the conveyor to fill his bucket with bedding material. He then can distribute the material to the work zone. These are usually employed in tight access jobs (like single lane closier pipline jobs) where a loader can not feed the trench directly.