The Beijing–Guangzhou–Shenzhen–Hong Kong high-speed railway or Jingguangshengang high-speed railway from its Chinese name is a high-speed railway corridor of the CRH passenger service, connecting Beijingxi Station in Beijing and Futian Station in Shenzhen. 

It crosses the border and follows Guangzhou–Shenzhen–Hong Kong Express Rail Link Hong Kong section to West Kowloon Station in Hong Kong. 

It is 2,230 kilometres (1,390 mi) long, and is the only Chinese high-speed railway to cross a border that requires immigration and customs clearance. The existing, conventional Jingguang railway runs largely parallel to the line.

The line forms part of the Beijing–Harbin, Beijing–Hong Kong (Macau) passageway, based on the "Eight Verticals and Eight Horizontals" railway master plan announced in 2016.

Construction started in 2005. The Wuhan–Guangzhou section opened in December 2009, the Guangzhou–Shenzhen section opened in December 2011, the Zhengzhou–Wuhan section opened in September 2012, and the Beijing–Zhengzhou section was opened in December 2012.

The 36-kilometre (22 mi) cross-border Shenzhen–Hong Kong section opened on the 23rd of September 2018. The line is the world's longest high-speed rail route. The high speed rail line cuts travel time by more than half. The line fully opened on September 23, 2018.

According to en.wikipedia