Relatively few overseas firms have helped China build infrastructure because the government distrusts foreign interests in top-priority state projects, hiring them only when local talent is found unqualified. But those who look at the fine print on infrastructure projects in China will eventually see the name ThuyssenKrupp (TKA.DE). The German metal worker opened its Asia headquarters in Shanghai in 2003. In just its first few years it was selling 60,000 elevators annually to China and had sold technology for the Shanghai airport maglev airport train. Its share prices have fallen a steep 62% since July 2011 but mostly in tandem with the global market slump in August. Another one to follow, Thales SA (HO.PA), once won a $21.6 million contract for equipment and service at an airport in southwestern China. China's infrastructure momentum puts a solid support beam under the entire world's No. 2 economy, not just individual companies. When China booms, emerging markets elsewhere tend to tag along and investors in other countries feel warm and safe about risky assets -- meaning stocks as a whole won't fall through the floor. This article is commentary by an independent contributor, separate from TheStreet's regular news coverage.