Five swivel bridges completed synchronous rotation and docking at a railway construction site in Beibei district of Chongqing on early Friday morning, setting a series of new records in the field.

The success has laid a solid foundation for the wide application of road overpasses in the future. As the traffic network around big cities becomes ever more dense, more overpass bridges crossing major urban roads and railways will be needed, said Zhang Wenxue, an expert on swivel bridges and professor of architecture and engineering at Beijing University of Technology.

Speaking of Friday's docking, he gave some of the parameters:

"The heaviest bridge weighs 4,500 tons and five bridges weigh a total of 21,500 tons, equivalent to the weight of 15,000 cars," he said.

To ensure railway safety, the rotation was conducted early on Friday from 0:33 am to 1:55 am, with three bridges on the left line and two on the right.

"The total weight is heavier than that of the four rotation bridges at Beijing Daxing International Airport, which was 11,500 tons. The total length of the five bridges is 383.5 meters," Zhang said.

More than 120 people participated in the project and more than 100 precision checkpoints were set up. The five bridges had to rotate simultaneously within 90 minutes — a narrow time window in light of busy railway traffic.

Zhang said the simultaneous rotation of five bridges has set some new records, including the largest number of swivel bridges in a large-span cluster and the heaviest structure having more than three large-span cluster rotations.