BEIJING — China plans to increase its high-speed railway network, already the world's biggest, by adding 2,000 km of new lines in 2020, according to the country's railway operator.

By the end of 2019, the country's high-speed railway operation mileage reached 35,000 km, which increased more than 5,000 km from one year earlier and accounted for nearly 70 percent of the world's total, according to the China State Railway Group Co Ltd.

The country plans to expand its railway network by more than 4,000 km in 2020, up from 139,000 km at the end of 2019, the company said.

It said the country's railway investment totaled 802.9 billion yuan (around $115.19 billion) in 2019, but did not reveal detailed investment plans for 2020.

A total of 3.85 billion passenger trips are expected to be made by railways in China in 2020, up from 3.57 billion in 2019.