Chongqing- Urban railways support modern metropolitan areas to alleviate traffic problems. Recently, a dual-powered urban express was put into operation in the mountain city of Chongqing, the first of its kind in China. World-renowned metropolitan areas such as Tokyo and Paris have built several extensive urban railway networks, enabling one-hour commutes between the metro area and its surroundings.

Referring to international and domestic experience, expanding the construction scale of rapid rail transit networks is an excellent manner to alleviate the "urban disease." In London, nearly 80% of the trips to the city center during peak hours are realized through the urban express; In Chinese city clusters like Beijing-Tianjin- Hebei and Pearl River Delta, urban express is also used to alleviate high-intensity and high-frequency travel demand.

The urban express is the short term for the rail transit express line network in the city's metropolitan area, including the urban express line and the urban (suburban) railway. The express line can only be called when its speed reaches 100-160 kilometers per hour, with the characteristics of fast speed, large traffic volume, and public transportation.

China's first dual-powered tram in innovation

Bringing benefits to the industrial parks along the line and enhancing the radiation capacity of the business districts, the launch of Southwest China Chongqing's Jiangtiao line creates a metropolitan on the rail and forms a one-hour commute circle.

This further effectively improves the connectivity of the Chongqing urban area and even the Chengdu-Chongqing city clusters.

As Chongqing's first suburban railway, the Jiangtiao line stretches from Tiaodeng Station of CRT Line 5. It ends at Jiangjin Binjiang New City, spanning Dadukou District, Chongqing High-Tech Industry Development Zone, and Jiulongpo District, linking Chongqing's central downtown and suburban areas, with a total length of about 28.22km. 

Due to its special topographic features, Chongqing seeks breakthroughs in technological innovation. For example, the dual-powered system technology is adopted for the Jiangtiao line, enabling the trains to operate under two different power supply systems: AC (Alternating Current) and DC (Direct Current). This technology was the first adopted in China, making the Jiangtiao line the first dual-powered line in China.

According to the relevant person in charge of Chongqing City Transportation Development and Investment Group Co., Ltd., this technology fills the technical gap in China and is also at the top level globally. This way, more scientific and technical elements and innovative factors will be injected into the construction of the urban express. 

Cost-effective and green urban express 

In Chongqing, the urban express runs through the central urban area and radiates Chongqing's metropolitan area. Generally, the distance between stations is about 3-5 kilometers, and the service range covers 50-100 kilometers.

According to space planning, Chongqing's main urban metropolitan area accounts for 30% of the city's total area, bearing more than 66% of the population and 78% of the gross domestic product (GDP). 

Chongqing is a city of mountains and rivers, presenting a multi-centered and clustered urban layout. Under the spatial scale of a supercity with an area of 28,700 square kilometers, the urban express meets the needs of medium and long-distance travel. Meanwhile, the construction cost of the urban express is lower than that of the expressway, which is more conducive to green development.　　

Currently, in the Chongqing metropolitan area, the distance from the central urban area to the distant districts and counties is more than 100 kilometers with high expressway traffic flow. In 2020, data shows that the proportion of commuting over 60 minutes in Chongqing was 17%, and the commuting space radius was 40 kilometers, second only to Beijing and tied with Shanghai for second in the country. 

(Tan Jingyue, as an intern, also contributed to this report.)