Picture this. A wheeled excavator, Cat has one. They make rail boggies that attach to the undercarriage. You drive onto the tracks and when your mulching, for saftey, you put down the outrigger's. Multi-purpose machine and has to be cheaper than that rail car. Could be done with a tracked excavator as well but getting onto the tracks would be a little more difficult. Look at that rail car again. The boom's are straight off an excavator. I would hate to see the build cost on that unit, plus it looks railroad owned and that is bad news for the contractor.