When the yellow iron runs, we make money” is a common adage for heavy/highway contractors. Yellow iron – that is, the bulldozers, excavators, backhoes, rollers, scrapers, and graders that heavy/highway contractors operate – is the company’s most essential asset. For a heavy/highway contractor, construction equipment is the equivalent of a manufacturer’s machinery; it can’t perform the job without it. If the yellow iron is running, then the company is doing work.