In this series I'll show the build process for a modular tank car to go on the 7.5" narrow gauge flat car. This is meant to look like a shopbuilt load that you might see in the old days. I used an old scrap air compressor tank and fabricated all the details. In Part 1, I preprared the tank by removing the brackets, fabricated a dome from a piece of 4" pipe, and made a removable end for storage. I review some techniques for laying out parts including transfer punches, scribing the dome base to fit the curved tank profile, dial indicators, dial calipers, and other simple tools and techniques.