Hundreds of workers at a factory in Shenyang in northeastern China weld automated machines, 95 yards long, that are used to bore subway tunnels. At another factory there, employees assemble robots that China¡¯s solar panel makers will use to streamline their production.

Shenyang is the capital of Liaoning province, one of three large provinces in the northeast that constitute the cradle of China¡¯s heavy industry. Now the central government, confronting a national economy that has slowed because of a real estate crisis that defies easy fixes, is turning to cities like Shenyang. It hopes to squeeze more productivity and efficiency out of the region¡¯s factories.

But those factories tell only part of the story of the economy of northeastern China, underlining the challenges facing Beijing policymakers, who are turning to what many economists believe is a tired playbook.