In the early hours of November 19, beside the Lashihai Station on the Yunnan-Lijiang-Shangri-La Railway at an altitude of 2,487 meters, a yellow-and-blue domestically produced new-generation continuous tamping and stabilizing machine steadily advanced along a long, steep gradient of 28.5‰, accurately completing both continuous and step-by-step operational tests. This specialized performance test targets the complex conditions of high altitude and steep gradients, marking the first time China’s independently developed new-generation intelligent large-scale track maintenance machinery has taken on the core challenges of the Lijiang-Shangri-La Railway.

In recent years, with the continuous advancement of railway construction in multiple plateau regions across China, high-altitude environments with steep gradients and variable slopes have become increasingly common. This has given rise to the new generation of intelligent large-scale track maintenance machinery, developed with complete independent intellectual property rights in China. After its debut at CRCC Equipment in December 2024 and its first appearance on Yunnan railways in June 2025, this round of tests focuses on the extreme 28.5‰ gradient and sections with slope variations ranging from 12‰ to 28.5‰ along the Lijiang-Shangri-La Railway. Conducted across four maintenance windows, the tests comprehensively evaluate continuous and step-by-step operations under scenarios involving uphill, downhill, and varying gradients.

“This is not only a comprehensive assessment of the equipment’s performance but also a crucial step in accumulating key data for the automatic step-by-step operations of subsequent turnout tamping machines,” explained Yang Dong, deputy director of the Track Maintenance Workshop No. 1 at the Kunming Track Maintenance Machinery Depot under China Railway Kunming Group. During operations, the new-generation large-scale maintenance machinery fully leverages the core advantages of its internal combustion electric drive traction system, overcoming the “altitude sickness” issues that traditional large maintenance machines face in high-altitude regions. Its intelligent analysis and control system automatically identifies gradient parameters and adjusts operational settings in real time with precision, effectively addressing the critical bottleneck of speed control on long, steep gradients and achieving dual improvements in both operational efficiency and quality control.

To ensure the safe and orderly progression of the tests, China Railway Kunming Group meticulously formed a specialized testing team. Every aspect, from track inspections and vehicle preparations to emergency support, was strictly managed. Facing harsh conditions such as significant altitude variations and thin air, the operational personnel demonstrated a strong sense of responsibility and mission, ensuring the entire testing process remained safe and controllable.

“After six months of field testing, the new-generation large-scale track maintenance machinery has fully adapted to the maintenance demands of various complex environments. Whether dealing with oxygen-deficient conditions at high altitudes or operational challenges posed by steep gradients, it performs with ease,” said He Jinquan, a research and development engineer at CRCC Equipment.

The success of the gradient tests on the Lijiang-Shangri-La Railway fully validates the operational efficiency and safety of the domestically produced new-generation intelligent equipment under complex working conditions. It also signifies a technological leap for China’s large-scale track maintenance machinery, expanding its capabilities from plain-line operations to challenging plateau environments. This advancement will provide more efficient and reliable maintenance solutions for railways in plateau regions.