• • Carbon emissions from China's railway sector increased by 11.2% from 57.7486 million tons in 2016 to 64.2084 million tons in 2021, with indirect emissions from electricity rising from 68.8% to 78.8% of total, underscoring the need for grid decarbonization.
• • Energy consumption intensity decline cut emissions by 18.8654 million tons, but carbon emission intensity, economic benefits per unit turnover, and operating capacity collectively added 25.3252 million tons, indicating that efficiency gains were offset by growth in activity and economic factors.
• • Spatially, emissions were higher in eastern China; Shanghai, Beijing, Guangzhou, and Chengdu bureaus had the highest emissions (555.71, 513.90, 458.78, and 427.49 million tons respectively), reflecting regional economic disparities.
• • Dominant driving factors varied across 18 bureaus: operating capacity was the main promoter for 7 bureaus (e.g., Taiyuan, Beijing), while economic benefits per unit turnover was the main promoter for 10 bureaus (e.g., Shanghai, Guangzhou), and Harbin was uniquely driven by energy consumption intensity, highlighting the need for tailored mitigation strategies.