CHANGCHUN, July 1 (Xinhua) -- The first phase of the fully underground metro Line 1 officially began operation in Changchun, capital of Jilin Province Friday.
Changchun has become the fourth city in northeast China to open a metro line, following Shenyang, Harbin, and Dalian which opened their first subway lines from 2010 onwards. The city's public transport system already includes two above ground light rail lines.
The construction of the subway line began in September 2011 with a total investment of 16 billion yuan (2.36 billion U.S. dollars). The 18.1-kilometer-long line runs from north to south passing through 15 stations.
To allow the subway line to operate normally in cold weather, Changchun Railway Vehicles Co., Ltd. developed a temperature-resistant train carriage. The inner layer of the doors and windows is filled with argon and the exterior glass is coated with heat insulation film.
According to Xu Huixue, the company's design manager, the subway can run normally at sub-zero temperatures as low as minus 35 degrees Celsius, earning the design the name "little snow leopard."
The subway design is also energy-saving, with reduced energy consumption due to an advanced air-conditioning system using a high-performance thermal insulation design, frequency conversion, and a heat pump.
Changchun was one of the first Chinese cities to plan a subway system. However, a lack on investment meant the city had to wait a long time for construction to begin.
In recent years, the increasing number of vehicles on the road has caused traffic jams in the city, forcing it to speed up the construction of its subway system.
"Because of the subway, we can now drive less," said Zhang Haoran, a Changchun resident.
Chinese cities are increasing pushing forward the development of rail transit systems. Figures from the National Bureau of Statistics showed that China had 4,153 kilometers of urban rail networks in operation across 30 cities as of the end of 2016.