After the "Train to Spring" became a trending topic, Chongqing's "Train on the Cloud" has once again gone viral on the internet. As the train of CRT Line 6 passes over the Caijia Jialing River Bridge shrouded in mist, it looks like it is traveling on the clouds.

The rail transit bridge is a unique part of Chongqing, the "City of Bridges."

Caijia Jialing River Bridge is not the only rail transit bridge in Chongqing that has come into focus. Qi Yong, Manager of Rail Transit Bridge of Bridge Division of T.Y. Lin International China, has participated in designing many rail transit bridges, including the Jiahua Rail Transit Bridge, the Nanjimen Yangtze River Bridge, and the Caijia Jialing River Bridge. Here's his introduction to the features of these rail transit bridges.

Caijia Jialing River Bridge on the Cloud

Completed in 2013, the Caijia Jialing River Bridge is a cable-stayed bridge consisting of north and south approach bridges and the main bridge with a length of 640 meters and the biggest span of 250 meters. The main bridge deck is 100 meters away from the river bed.

"On cloudy days, the bridge is shrouded in mist, as if it is above the clouds," Qi said that this is because the bridge is located in a river valley, and Chongqing's climate is humid, making it easy to generate advection fog. Hence it gives the impression of a train passing over the clouds.

In addition, the cross-river bridge usually used for road traffic is generally about 30 meters wide, making it look slightly "clunky." However, the Caijia Jialing River Bridge is a cable-stayed bridge with high piers and a narrow deck. The main bridge is only 15 meters wide, presenting a gracefully slender beauty on the clouds.

Jiahua Rail Transit Bridge Passing Through the Building

Jiahua Rail Transit Bridge is located between Hualongqiao and Lijiaping stations, about 100 meters upstream of Jiahua Bridge. It is a key control project for the newly opened Phase I of Line 9 across the Jialing River. With a length of about 620 meters and a width of 12.5 meters, it is a continuous steel frame bridge. It adopts the closure method of the overall lifting of a 92-meter-long steel box girder in the middle of the main span.

What attracts the most attention is that after passing over the Jiahua Rail Transit Bridge, the train passes through the commercial podium building in the middle part of the Vanke Center, becoming the second "Train Passing Through the Building" in Chongqing after the train of Line 2.

"Thanks to an integrated design, the station hall will have direct access to the commercial podium building after opening the building. The perfect combination of the station and the shopping mall will further facilitate the flow of passengers." Qi said that the Jiahua Rail Transit Bridge has the same shape and structure as the existing Jiahua Bridge to ensure the city's beauty and traffic safety. As a prefabricated steel truss-concrete composite continuous rigid frame bridge, Jiahua Rail Transit Bridge has the largest span of its kind.

Terrain, Rail, and Design in Harmony

With the gradual improvement of the rail transit network, an increasing number of rail transit bridges spanning the Yangtze River and Jialing River have sprung up based on the geographical conditions of Chongqing, a mountain city surrounded by two rivers.

"Generally speaking, a combined highway and railway bridge can be used when construction conditions permit, such as Guojiatuo Yangtze River Bridge, Baijusi Yangtze River Bridge, and Zengjiayan Jialing River Bridge," Qi said. Otherwise, a rail transit bridge can only be applied.

The river-crossing rail transit bridge often has a large span and a narrow width due to the need to meet the requirements of train operation in terms of structural stiffness and landscape characteristics.

According to Qi, the rail transit bridge has become a new name card of Chongqing, the "City of Bridges," as it adapts to the mountainous terrain and the rapid rail transit development with its innovative design.