Area Rail Transit begins revenue service to Larkspur Landing, facilitating a rail-ferry link to San Francisco. Novato Downtown station, an infill station, is opened the same day. December 15 – Copenhagen–Hamburg freight traffic transferred wholly to rail, ending rail freight usage of Baltic train ferries. December 16 – Qingdao Metro Line 2 extended to Taishanlu from Zhiquanlu. December 20 – Guangzhou Metro Line 21 extended to Zhenlong West from Yuancun. December 25 – Xiamen Metro Line 2 and Suzhou Rail Transit Line 3 began operation. – The first scheduled passenger train crosses the Crimean Bridge. December 26 – Hefei Metro Line 3 opened. December 27 – Chengdu MetroLine 5 opened, Line 10 extended to Xinjin, Tram Line 2 extended. December 28 – Ji'nan Metro Line 3 opened; extension sections of Tianjin Metro Line 1, Zhengzhou Metro Line 2 and Guiyang Metro Line 1 opened. December 29 – Line 1 of Hohhot Metro opened – The Loop Trolley in St. Louis, Missouri ceases running after just over 13 months of operation. December 30 – Beijing–Zhangjiakou intercity railway, Zhangjiakou–Hohhot high-speed railway and Datong–Zhangjiakou high-speed railway begin operation – Extension sections of Chongqing Rail TransitLoop line and Line 1 opened. – Gaoming Tram begins operations, Line T1 of Songjiang Tram extended to Xinqiao railway station. References Rail transport Transport timelines by year