Last week China’s largest railway equipment maker CRRC signed a $650m deal to supply underground carriages to Los Angeles, in what has become known in Washington as a “tweetable result’.

As Donald Trump prepares to welcome Xi Jinping to his Florida resort on Thursday, such contracts represent a rare opportunity for agreement between two men whose governments have taken seemingly irreconcilable positions on everything from the North Korean nuclear crisis to Beijing’s maritime claims in the South China Sea.

One of the few things the Chinese president could easily offer his US counterpart is more Chinese investment in infrastructure and America’s manufacturing heartlands, whose voters propelled the US president to victory in last November’s election. But even such mutually beneficial investments have courted controversy — in both countries.