What is Express Rail Link? The 26-km long Hong Kong Section of the Guangzhou-Shenzhen-Hong Kong Express Rail Link (Express Rail Link, or XRL) runs from West Kowloon in Hong Kong to the boundary of Hong Kong and Shenzhen. The Express Rail Link will connect with the 16,000-km National High-speed Railway Network and will enhance Hong Kong's role as the southern gateway to the Mainland. Construction of the Express Rail Link commenced in January 2010, with completion targeted for 2015.