There are north-south and west-east trunk lines in China. The north-south line, with Beijing as its hub, consists of the Beijing-Guangzhou Railway, Beijing-Shanghai Railway, Beijing-Kowloon Railway and Beijing-Harbin Railway. The west-east line, with Zhengzhou as its hub, consists of the Lianyungang-Lanzhou Railway and Lanzhou-Urumqi Railway. The latter has been extended westward to link up with the railways in Kazakhstan. Thus Asia and Europe are linked by railways from Lianyungang in China to Rotterdam in Holland. New railway lines have been built in mountainous areas in southwestern China, mainly the Chengdu-Chongqing Railway, Baoji-Chengdu Railway, Chengdu-Kunming Railway and Nanning-Kunming Railway. Besides, the Turpan-Kashi Railway has been newly built in the Xinjiang Uygur Autonomous Region.