Workers for China Petroleum Engineering & Construction Corp. (CPECC) talk on a mobile handset by oil storage tanks near Melut, in the Upper Nile, Sudan.Photographer: Trevor Snapp/Bloomberg[/caption] When Uganda sought bids last month for an $8 billion contract to expand the East African nation’s rail network, it only invited Chinese companies to apply. That condition, agreed to by the Ugandan and Chinese governments, illustrates the hurdles President Barack Obama must overcome as the U.S. tries to challenge China’s status as Africa’s No. 1 investor and trading partner. China’s trade with the continent exceeded $200 billion last year, more than double that of the U.S, which it overtook five years ago. Obama will step up his efforts to forge closer ties with Africa when he hosts more than 40 of the continent’s leaders at a summit in Washington next week. While the World Bank projects African growth of 4.7 percent this year, the U.S. is looking beyond securing deals and access to a consumer market of 1 billion people to promoting democratic principles and countering Islamist-inspired security threats from Nigeria to Kenya. “China has got a massive head start,” Daniel Silke, director of Cape Town-based Political Futures Consultancy, said in a July 23 phone interview. “From both a diplomatic and economic point of view, China has made all the running over the last few years so there is quite a catch-up for the U.S.” China has held five conferences with ministers and leaders across Africa since 2000 as it fosters ties with a continent that provides both resources and a market for manufactured goods. Nigeria has the potential to be one of the world’s top 20 economies by 2030 with a consumer base exceeding the current populations of France and Germany, New York-based McKinsey & Co. said in a report last week.