Does the Qinghai-Xizang Railway also have a "warmer pad"?

Yes. Its official name is the switch snow-melting system, and it has been operating steadily on the snowy plateau for 22 years.

As early as two years before the railway opened to traffic, this set of equipment underwent extreme cold, high wind, and low-oxygen tests under harsh conditions, exploring switch anti-freezing experience for the world-class plateau railway. With the full opening of the Qinghai-Xizang Railway, the switch snow-melting system was officially put into use, filling the gap in China's independent switch snow-melting technology for plateau railways and completely breaking foreign monopolies.

Today, this domestically produced intelligent snow-melting system has become the standard safety equipment for all high-altitude and high-cold railways across the country, marking a historic leap from follower to global leader.

The "warmer pad" on the steering wheel

"Switch snow-melting has a magic tool -- it heats automatically to melt hard ice; smart sensors start and stop precisely, ensuring safe train operation." This jingle, popular at the Amdo Signal Work Area of the Lhasa Infrastructure Section, vividly sums up the core function of the switch snow-melting system.

The working principle of this "magic tool" is to convert electrical energy into heat, with electric heating elements arranged on the rails continuously generating heat to melt snow and ice in the switch area. To understand its value, we must first start with the switch itself.

The switch is vividly called the "steering wheel" of the train. Its core steering component, the switch rail, switches precisely according to the train's travel route, guiding the train to move smoothly from one track to another to complete operations such as lane changing and train meeting.

"The switch rail fits tightly against the fixed stock rail, and the gap between them is so small that not even a coin can fit in. Once it gets stuck by snow or ice chips, the switch rail can no longer move," said Zhang Xiaozhong, foreman of the Amdo Signal Work Area. "It's just like the steering wheel being frozen solid. The train cannot pass on schedule as planned, and can only change its route or stop and wait, which can easily lead to railway operation accidents."

The Golmud-Lhasa section of the Qinghai-Xizang Railway is 1,142 km long, of which 960 km are above 4,000 metres in altitude, crossing the Tanggula Mountain pass at 5,072 metres and running through 550 km of permafrost zones.

"It's almost always 'winter' or 'almost winter' here. Especially from September to June of the following year, heavy snow can come without warning," Zhang Xiaozhong said,"the outdoor environment is full of strong winds and extreme cold, and it's even hard to breathe, so we need to be extra careful. Fortunately, this 'close-fitting heater' on the switch stands guard in the wind and snow for us."

Extreme environments are the greatest challenge, but also the natural testing ground for iterative upgrades of domestic equipment. Zhao Yunchao, a staff member from Jilin Jinlun Technology Co., Ltd., the developer and manufacturer of the switch snow-melting system, explained that more than 20 years of high-plateau operational data have provided unique core experience for localised improvement, domestic production upgrades, and intelligent iteration of the equipment.

"Over the 20 years since the railway opened, there has never been a single operation interruption caused by switch snow and ice or snow-melting equipment failure," Zhang Xiaozhong remarked, "it has stood the test of extremes and is our most reliable partner in frontline maintenance."

First generation -- starting from "clumsy"

The first-generation "warmer pad" was far from being as "smart" as today's version.

Its electric heating elements were entirely imported, and everything was manual -- the heating bars heated constantly, with no automatic shut-off or intelligent sensing.

Thus, operation was cumbersome: signal workers had to forecast the weather in advance, turn on the power if they expected snow, and after the snow stopped, they had to make another trip to the site, personally confirm that the ice and snow had melted, and then manually cut off the power.

A turning point came in 2008, when Jilin Jinlun Technology Co., Ltd. built an independent production line for electric heating elements. This marked the "zero to one" domestic breakthrough of the core components in China's railway industry, and the switch snow-melting technology finally had its own "Chinese core".

"Manual snow removal is simply not feasible at high altitudes. You shovel a scoop of snow, and the wind blows it right back. The gap of the switch rail you just cleaned will form an ice shell again in a few minutes as the melted snow water freezes," said Liu Suiyi, foreman of the Tuotuo River Signal Work Area. "It takes one person an hour to shovel the snow, but the equipment can melt it in just 15 minutes. The most valuable part of the first-generation equipment is that it uses technology to stand in the harshest snowstorms instead of people."

It was precisely from this "clumsy" equipment that China's switch snow-melting technology blazed its first path towards independence.

Second generation -- Learning to "think"

Targeting the shortcomings of the first-generation system, Qinghai‑Xizang Railway Group launched technical research in 2017, focusing on three core areas: hardware optimization, sensor upgrading and intelligent control, to fully promote localized research, development and transformation.

In 2019, the switch snow-melting system achieved 100% domestic hardware and software, and the new second-generation intelligent "warmer pads" were gradually installed and put into operation on the Golmud-Lhasa section.

All core components are custom-made for plateau conditions, and can operate continuously for 24 hours in an environment with a temperature range of -40°C to 45°C, strong sandstorms and oxygen deficiency, fully adapting to various switch working conditions in permafrost areas.

The replacement work was carried out in a "forbidden zone for life."

"We lived in tents and prefab cabins in the wild, and for long periods we shared the neighbourhood with wild animals," Liu Suiyi recalled, "we could see wolves and Tibetan antelopes from time to time, separated by the wire fence. We all kept to ourselves, and it was a unique kind of company on the plateau."

The really tough part was the thousands of times of standing up and bending down.

"We had to remove the old electric boxes on each sleeper one by one, and unscrew every single U-shaped buckle that fixed the cables," Liu emphasised, "that was the most time-consuming part."

When all the cables were sorted and integrated into a single branch box, the rail surface became neat and tidy. He felt a huge sense of relief, "after the structure was simplified, the daily maintenance work became more than twice as easy."

Today's second-generation "warmer pad" has been completely transformed.

The system consists of a remote control center, station terminals, electrical control cabinets, heating elements, weather stations and rail temperature sensors, building a fully automatic + manual backup dual-mode intelligent operation and maintenance system, which truly realizes independent perception of equipment, independent system regulation and independent fault warning.

The core change is that it has learned to "think." Sensors collect real-time data, and a dynamic algorithm automatically switches between intermittent heating, emergency heating, and constant-temperature insulation modes, reducing overall energy consumption by more than 25% -- achieving a precise balance between snow melting and energy saving.

Intelligence not only brings efficiency improvements, but also reduces costs. The procurement cost is 40% lower than imported products, and the operation and maintenance cost is reduced by 50%, making the system truly "affordable, low-cost to run, and easy to use".

"Digitalisation" builds a fortress for "unmanned" operation, but "unmanned" does not mean "unguarded." Behind every switch that allows a train to pass safely, there is a signal worker ready to act at any moment.

"The equipment is growing, and so are we," said Zhang Xiaozhong, "but one thing has never changed -- as long as there is still a chance of snow on the switch, we will always be there."

Reporter: WanJing

Translator: Luo Rongting, Zhi Xinghua

Review: Phurbu Tsering, Drakpa Wangchen