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In the early morning of April 8, the construction site between Xujiacao and Wangchun Bridge on Ningbo Rail Transit Line 1 was abuzz with mechanical equipment and flying welding sparks. Over 50 construction workers performed their respective duties, completing the welding of 4 rail heads in three hours. This marks the official launch of the 2025 overhaul and rail replacement project for Line 1 undertaken by the company.
Flash-Butt Welding Operations
This round of overhaul construction involves the replacement of 1.275 kilometers of rails in two sections: Xujiacao to Wangchun Bridge, and Donghuan South to Qiuaidong. Work is primarily carried out from 0:00 to 3:00 every morning. At 0:45 that day, with the issuance of the "skylight" operation order, a fleet of rail vehicles equipped with new energy rail welding machines traveled to the construction section. Coordinating with on-site commanders, the vehicles reached their designated work positions and stabilized to prepare for welding. Following the go-ahead for operations, construction workers entered the track area with tools, diving into the intensive construction work. Rail joint alignment, end-face rust removal and grinding… each process advanced in an orderly manner, creating a bustling scene at the site.
At 1:25, workers used a portable small crane to precisely adjust the horizontal and vertical alignment of the rail joints. Accompanied by the "hissing" sound of the flash welding machine and the glow of sparks, the first rail "bone-setting" operation was successfully completed. Two new rail sections were successfully welded together through high-temperature fusion welding. Flash-welded joints achieve a strength of over 90% of the base material, featuring high weld smoothness and reliable joint strength, better meeting the high-quality and efficient welding needs of urban subways. "The first welding is complete." "The second group of rails is aligned and waiting for welding." Calls from walkie-talkies came one after another. One team quickly cleared welding slag from the welding and flash-butt trimming processes, while another immediately moved on to grinding and aligning the next group of rails. Each process achieved seamless integration through the tacit cooperation of the workers.
It is reported that to ensure the smooth completion of this overhaul task, the Ningbo Rail Transit Line 1 Maintenance Project established a quality and safety leading group. The group scientifically planned the construction process and strictly supervised every detail, including rail welding type tests, safety education for personnel entry, and pre-shift technical disclosures. By operating at "full capacity," they aim to ensure the construction "progress bar" stays on track, providing a solid quality guarantee for the upcoming passenger travel peak during the "May Day" holiday.
Source: New Transport Company of China Railway First Bureau