JUST OVER 25 years ago Shanghai launched its subway with a single, stubby line. Since then it has added 15 lines and some 700km, making it the world's longest metro system. It's far from done. The city recently unveiled plans for another 300km, including overland rail, within five years. Much of the work proceeds as machines drill tunnels beneath the surface. But excavation holes around the city offer about the activity deep underground.
They are part of a nationwide push. The Chinese government has, in the words of state media, hit the "fast-forward button" on infrastructure spending, and tried and tested way to the economy. In the first quarter China's GDP grew by 6.4% compared to a year earlier, level with the final quarter of 201