Trucks line up to pass through the Manzhouli Land Port in Manzhouli, Inner Mongolia autonomous region, in December. XIAO JIANBO/XINHUA Russian freight trains inch across the border into Manzhouli, their cars laden with grains and oilseeds from the fertile fields of Siberia and the Russian Far East. Within days, these raw imports are cleared, processed in towering local factories, and dispatched to kitchens across China.