If you are using the automatic GMAW welding in the short circuiting mode, you realize you will have to ultilize automated UT for inspection, right? Radiography will not be able to find the Incomplete Fusion that will be your most common defect. Especially at those wall thicknesses, unless your welders are well experienced in that welding process. You an use RT for your tie-ins and any other manual welds. If the mountainous area is rocky, you of course will have to blast the rock prior to trenching. Or you can use a Trenhcor trenching machine to dig your trench. I am assuming your auto welding machine has an internal line-up clamp. If so, you may need to use an additional external line up clamp to help with the misalignment caused by the out of roundness of the pipe. Usually an internal line up clamp does not have the strength to fit the pipe up at those wall thicknesses. For auto welding, you want to keep your offset at a minimum or have a small welder that can climb in and backweld. However, that is very time consuming and dangerous as well. I also recommend, based on past experience you qualify your procedure using the thickest wall thickness you will encounter. As far as pipe transport, I don't know of any way except to truck it in on your right of way and use sidebooms to offload and string it. Are you crossing any major roads that are heavily traveled? You may need to thrustbore in those areas rather than open cut the road. Those areas as well as residential areas may require a heavier wall thickness, which would probably require seperate hydrotesting. Hydrotesting is the easy part. You can hydrotest between valve sites or pig launcher stations. Just make sure you install vents at all high points. If you do not get all of the air out, you will not be able to maintain pressure. You will need to do a 24 hour pressure test after a 2 hour strength test and of course drying and swabbing afterwards before layup, unless you plan to introduce gas immediately. Tsai Chien for now.