After a construction boom spanning nearly two decades, China’s high-speed rail network has made record-breaking strides. But to ensure long-term sustainability, analysts said the government needs to address challenges around commercial profitability and mounting debt.The warnings came ahead of the next five-year plan, covering the years 2026-2030, in which policymakers will decide whether to take on more debt to expand the 48,000-kilometre network – already the world’s largest, surpassing the...