"Ice Phoenix" snowfield test run-40 degrees Celsius can also fly as usual
The unique stunt of the Alpine EMU
At 7:50 on August 15, Mudanjiang High-speed Railway Station in eastern Heilongjiang Province.
With the sound of the whistle, a group of silver-white Fuxing EMUs slowly started and drove towards Jiamusi City.
This is the first test run of the Fuxing EMU on the Mujia High-speed Railway, the easternmost high-cold high-speed rail line in China.
The EMU model tested this time is the "Ice Phoenix" (CR400BF-G), a member of the Fuxing Alpine EMU series.
It was named because of the two golden ribbons on the front of the car like a phoenix spreading its wings.
"Ice Phoenix" is a high-cold high-speed EMU that has been technically upgraded on the basis of the Fuxing EMU "Golden Phoenix" (CR400BF). It operates in an extremely cold environment of minus 40 degrees Celsius.
The Fuxing Alpine EMU is the most frost-resistant model in the Fuxing family, with many members.
In addition to the "Ice Phoenix" unveiled this time, there are also a number of series such as "Alpine Crocodile", "Alpine Rabbit", and "Mixed-Blood Princess". The famous Jingzhang High-speed Railway Fuxing Intelligent EMU is also a member.
Ordinary EMU trains can only run in an environment of minus 25 degrees Celsius at most, while the "Fuxing" high-cold EMU can run smoothly at high speed in an extremely cold environment of minus 40 degrees Celsius or even lower, successfully solving the problem of railway operation in the high-cold area. This world-class problem.
Micron coating, special alloy——
Low-temperature resistant materials to create a cold-proof "golden bell"
In the severe winter in the Northeast, the temperature is often below minus 20 degrees Celsius.
People living here are familiar with such a phenomenon, that is, "having breathed into ice"-when the exhaled water vapor meets the ultra-low temperature outside, it instantly condenses into water and dew, forming a white mist.
This "condensation" phenomenon is a deadly killer for high-speed rail.
When a certain amount of water dew and dust are mixed together, a conductive pipe will be formed, which will cause a short circuit of the power supply, failure of electronic components and other faults.
The power line is precisely the vital "brain nerve" of Fuxing.
"An obvious difference between high-speed railways and ordinary railways is that apart from having a track under your feet, there is also a cobweb-like electrical contact net above your head. High-speed railways run fast because of this net that continuously transmits kinetic energy." China Zhang Kaixian, deputy director of the Chaoyang EMU of Beijing Railway Bureau Group Co., Ltd., told reporters, “The brain nerves of high-speed railways are most afraid of water. Hurt."
In January of this year, "Ice Phoenix" was launched for the first time on the Beijing-Harbin railway section.
In order to reduce the impact of condensed water on the power distribution cabinet, a layer of micron ceramic porous material is sprayed on the frame of the "Ice Phoenix" power distribution cabinet.
This material is fired at a high temperature and has many "honeycomb" pores inside, which can store water and dew for a period of time until the temperature around the cabin rises, and the dew can evaporate and escape along the pores of the ceramic material. , Thereby resolving the adverse effects of water and dew drops on the circuit.
Low temperature resistant materials are an important magic weapon for freezing resistance of high-cold EMUs.
From the exterior body to the key components, the materials used in the high-cold EMU have been verified by a large number of calculations and analyses and low-temperature tests, which meet the characteristics requirements of strength, fatigue, stiffness, and rebound in the low-temperature operating environment.
Embrittlement is a phenomenon that occurs in many materials at low temperatures.
According to Ma Kai, a senior engineer of CRRC Changchun Rail Bus Co., Ltd., the manufacturer of the high-cold EMU, the bolts and nuts between the upper side beam and the side beam of the underframe in the equipment compartment of the high-cold EMU are generally made of carbon structural steel. However, chromium-molybdenum alloy steel and other composite materials are used for the bolts and nuts of the high-cold EMU, which effectively reduces the risk of "fracture" of parts under low temperature conditions.
In addition, equipment compartments, sliding plug doors, equipment cabinets, etc., which are in contact with the outside cold air, are also replaced with special silicone rubber materials with a brittle temperature below minus 40 degrees Celsius, avoiding low-temperature brittleness and air leakage. Water leakage problem.
The water circulation system on the train is also afraid of cold. For this reason, the designers changed the material of the water pipes from copper to stainless steel that is not easy to be damaged by freezing, and then wrapped the pipes with a layer of cold-proof cotton. The pipe temperature can always be kept above 0 degrees Celsius without freezing.
Ma Kai said that there are still many anti-freeze and black technologies for the high-cold EMU.
In terms of materials, many high-performance materials independently developed by my country have made China's high-speed rail world-class cold-resistant experts.
Running in snow and ice, the heat generated by the train's electric heating device will quickly freeze the snow, and the thick ice layer becomes a major threat to driving safety.
For a while, my country's high-speed rail EMUs used imported paint to prevent icing, but the effect was not good.
In 2016, my country’s self-developed hydrophobic material coating came out. This coating imitates the "lotus leaf effect" in nature and can form an oil film on the key components of the EMU. Water drops cannot adhere to it, thus achieving waterproof and deicing. The effect.
In addition, the ultra-low temperature ductile iron independently developed by my country has also successfully solved the problem of low temperature adaptability of metal materials for high-speed rail.
In 2012, my country’s first high-cold high-speed rail, the Harbin-Dalian high-speed rail, was completed and put into operation. Ultra-low temperature ductile iron was used instead of materials imported from Germany in key components such as bogies. Low temperature test of 60 degrees Celsius.
Special switch, automatic anti-freezing function——
De-icing and snow-removing design allows the train to move forward in style
Ice melting and snow removal is the biggest challenge faced by railway operations in alpine regions.
In order to protect the train from ice and snow, designers have made special designs in many parts of the train.
The bogie is an important part of the smooth running of high-speed rail.
It is located between the train body and the track, and looks like a small car with four round wheels.
The train is relying on this group of "small wheels", running on the rails.
When driving in a windy and snowy day, the bogie is prone to snow and ice.
The bogie area of the high-cold EMU adopts a sealed structure and a protective design to prevent snow from entering.
Prevention is one aspect. When it encounters heavy snow and wind, the method of elimination comes in handy.
Harbin, Heilongjiang Province is located in the high-cold area. In 2012, my country was also the world's first high-cold line with a design speed of 350 kilometers per hour, the Harbin-Dalian High-speed Railway.
Since then, the Hazi high-speed rail and H-Mu high-speed rail have been opened one after another. In order to solve the serious problem of bogie freezing and snow accumulation, China Railway Harbin Bureau Group Corporation independently developed the first domestic "HTK-CBX0 type high-cold high-speed rail ice melting and snow removal device".
According to Li Yichen, an engineer at Harbin EMU, the traditional snow removal methods are generally workers using rubber hammers and high-pressure hot water trucks, which are inefficient. At most, there will be more than 200 people working at the same time.
The new snow removal method uses low-pressure warm water spraying, which can quickly peel off and melt the snow and ice on the bogie in all directions. The operator can also adjust the water spray pressure, temperature, and speed according to the ice accumulation of the EMU. Individuals can complete the snow removal operation of a group of EMUs in only 1 hour.
Special switch, this is another cold-resistant design of "Ice Phoenix" and other new high-cold EMUs.
The open string means that in an extremely cold environment, the viscosity of the grease inside the high-speed rail air switch will increase, which will easily lead to "arc phenomenon" between the positive and negative contacts. The current generates electric sparks in the air, just like a lotus wire connection, which leads to a circuit. The disconnection speed slows down and the control fails, which is very dangerous.
Especially high-speed railways are in high-speed operation, and the required voltage is also large. Once the "arc phenomenon" occurs, the destructive force will be even greater.
Therefore, the design and production unit has developed a new type of low temperature control switch for the high-cold and high-speed rail, which can be retracted and released freely even in cold weather.
There are many such special designs in high-cold EMUs.
For example, the train adopts a fully enclosed equipment compartment, and the ventilation grille adopts a "V"-shaped labyrinth design. The air can flow freely, but ice and snow cannot enter; the wheels have anti-skid and anti-lock functions. When abnormal wheel speed is detected, Automatically reduce braking force and traction, and increase friction through the sanding device to avoid wheel slipping.
In response to problems such as the icing of the EMU doors and platforms, and the freezing of the water pipes on the electric water heater, the drainage holes were modified and the heating wire was added.
In addition, the new high-cold EMUs also used automated anti-freezing functions in batches for the first time.
The relevant designers of CRRC stated that during the parking period of the train, the brake pads and brake discs of the bicycle were released for 55 seconds each time, held for 5 seconds, and each car cycled for 3 hours in turn.
To put it simply, it is to keep the brakes in motion all the time to "shake off" the snow to prevent freezing at low temperatures.
The designer also enlarged the gap between the brake pads and the brake disc to enlarge the gap between the friction blocks to prevent ice and snow from entering and affecting the brakes.
Dynamic tracking, big data analysis——
Improve monitoring facilities to escort travel
In the early morning, at the Harbin High-speed Railway Station, before the first EMU drove, a "Pathfinder" had set off first. This was the comprehensive high-speed rail inspection vehicle.
According to Han Xiufeng, Chief of the Power Supply Technology Section of Harbin Power Supply Section, under extreme cold weather, high-speed rail lines are prone to gauge changes and splits. Problems such as instability can easily cause power failure and parking.
The inspection vehicle will conduct a trial run every day. The 6C inspection system is installed on the vehicle. It takes 17 photos per second to help the staff observe the snow and icing conditions of the catenary parts and whether they are loose, missing, or damaged. Then the system monitors, Comprehensive diagnosis, etc., promptly discover and deal with existing problems.
The smooth operation of the Alpine EMU is inseparable from powerful and complete supporting facilities.
With the development of emerging technologies such as big data, these advanced technologies have also been used in the operation of high-cold EMUs.
Operational monitoring is an important guarantee for discovering and solving problems.
Along the Beijing-Harbin high-speed railway and other high-cold railways, the railway department has installed a monitoring system equipped with high-speed cameras, sensors and image recognition technology beside the track near the station, which can dynamically track and analyze the operation status and operation data of the EMU. If an abnormal phenomenon such as icing occurs, a grading treatment plan for ice melting and snow removal will be initiated.
In addition to monitoring snow and ice, the system can also monitor the operation of EMU components, improving the efficiency of inspection and maintenance.
The daily "physical examination" of the high-cold EMU mainly relies on big data analysis to find the "focus".
Guo Xiaodong, the onboard mechanic of the Chaoyang EMU of Beijing EMU, said that various equipment data is collected and uploaded to the "cloud" every day for statistical analysis, forming various charts, and some hidden dangers can also be exposed in advance through these data analysis.
In addition, the high-speed camera will also register high-speed rail line fasteners, vertical bolts and other equipment, and screen them one by one. In the extreme cold and snowy weather, use the anti-cold digital inspection instrument to collect and analyze data on site, and use sound wave, infrared and other flaw detection methods. Able to quickly measure equipment values.
The accumulation of these data not only played an important role in the smooth operation of the train at that time, but also provided valuable experience for the operation of other high-cold EMUs in the future.
The solid roadbed is an important guarantee facility for the operation of the high-cold EMU.
In high-cold areas, roadbeds are easily deformed due to frost heave.
Lu Yaorong, a researcher at the Chinese Academy of Railway Sciences, said that my country’s construction of the Qinghai-Tibet Railway also passes through permafrost areas. Due to long-term large-scale test and research work and basic and effective technical measures to deal with frozen soil for civil engineering construction, the Qinghai-Tibet Railway can be used all year round. Normal operation.
During the construction of the high-cold and high-speed railway in the Northeast, the construction party also borrowed from the existing technological achievements of the Qinghai-Tibet Railway and carried out some targeted innovations to successfully solve the frost heave problem.
For example, fill non-frost heaving fillers within the frozen depth of the roadbed, and install "insulation layers" on both sides of the roadbed slope toe.
In view of the problem that steel rails and switches are easy to freeze after being melted by snow, switch snow melting devices are installed in all stations, line stations, and EMUs on the whole line, and electric heating wires are pre-embedded under the switch rails.
Relying on complete facilities and powerful technology, China's high-cold EMUs continue to create world miracles.
At present, the CR400BF-G series, known as the "Ice Phoenix", has more than 60 Mercedes-Benz on the high-speed rail line.
my country's first high-cold EMU with a speed of 400 kilometers per hour, a transnational interconnection EMU, has also been successfully developed. It can operate at high speeds at an ultra-low temperature of minus 50 degrees Celsius, making it the world's most "freeze-resistant" high-speed EMU.
Our reporter Wang Yajing