China said Thursday it will build two new railway lines in its underdeveloped western regions to boost economic growth and ease pressures on existing routes.

One of the railways will be a 401-kilometer-long passenger expressway route linking Lanzhou, capital of Gansu Province, and Baoji, an important city in neighboring Shaanxi Province, the National Development and Reform Commission (NDRC) said in a statement Thursday.

It will connect northwest China with developed eastern China via an existing railway between Lanzhou and Xuzhou, an industrial city in Jiangsu Province, the statement posted on the NDRC website said.

The other line approved for construction will link Lanzhou with the capital city of southwestern China's Sichuan Province, Chengdu. It will be 463 kilometers long and pass through Jiuzhaigou, a high-altitude valley with lakes and waterfalls near the Sichuan-Gansu border.

"With NDRC approval, construction of the two railway lines will hopefully begin before the end of the year," said Chang Xiangli, an official in charge of transportation at the Gansu provincial commission of development and reform.

Chang said the new routes will slash travel time upon their completion in about six years.

"Trains will travel at 350 km per hour on the Lanzhou-Baoji route so the trip will take 1.5 hours compared with the current 7 hours," she said.

The Lanzhou to Chengdu train ride will take 4 hours, compared with the current 21 hours.