The most powerful chassis system for anti-corrosion and anti-chemicals and acids is the 3 coat polyurethane system. The primer consists of an aluminum pigmented moisture cured primer that was formulated for bridges in the mid-seventies. This heavy body primer does an amazing 8000 hours of salt spray, and once scratched rust will not travel beyond the scratch.
AG 111 polyester urethane was specifically designed for the New York City subway system to combat corrosion and graffiti. Polyester urethanes are the most expensive but they offer maximum chemical and acid resistance..
In 1988 I