Stretching 15,500 miles, China's "bullet train" network is already the largest in the world. By comparison, the second biggest high-speed rail network — in Spain — measures just 1,926 miles.

But by the end of 2018, China's will get even longer.

China Railway Corp, the country’s government-owned train operator, will soon finish the last phase of the Guangzhou–Shenzhen–Hong Kong Express Rail Link, a high-speed rail line spanning more than 80 miles.

Construction is near complete in Hong Kong, where China is building a 4 million-square-foot station for the new trains, as reported by The Hong Kong Free Press.

While the seven-year, $10.7 billion project is certainly impressive, it has faced much controversy surrounding its cost, its construction delays, and how it could affect Hong Kong's political autonomy.

Take a look below.