bringing the desert to new life

in 2023, on the first anniversary of the opening of ruoqiang-hetian railway, another new technology has been implemented on the line. with the trial operation of a new moving block train control system independently developed by china based on beidou positioning, the innovative technology of "beidou positioning train moving block tracking" has been successfully applied in the national railway for the first time. this major technological breakthrough laid a milestone for further improving the level of china's railway technology and equipment, and raising china's high-speed rail train control technology to a leading position in front of peers.

with a total length of 825 km, ruoqiang-hetian railway is an on-site demonstration of application of the new train control system. it constitutes the world's first desert railway loop together with ge'ermu-ku'erle railway and southern xinjiang railway - the taklamakan desert railway loop which not only put an end to the history when there was no railway in many cities and counties in the southern edge of tarim basin, but also promoted the coordinated development of border areas. therefore, it is of great significance to china's strategic national defense.

to build this lifeline in the desert, railway construction workers from all over the country traveled thousands of miles to southern xinjiang to undertake the challenging mission. many casco employees shed their sweat in the desert. they armed the ruoqiang-hetian railway with intelligent cutting-edge signaling technology, which helped the desert high-speed channel operate in a cost-effective manner.

ruoqiang-hetian railway in the desert

going all out to launch the new system

casco's task was to equip ruoqiang-hetian railway with a new type of train control system developed independently. "the new train control system is currently the most advanced one in the railway industry after the c3 system. it is benchmarked against the world's most advanced technology and was designed to realize the tracking of moving trains based on beidou satellite positioning. it is also one of the key research projects to implement china's "beidou " development strategy," said xu xianliang, senior manager of casco's new train control system project.

in august 2018, the new train control system was officially approved as a major scientific research project of casco. the company quickly organized the core backbones of multiple departments such as product, r&d, testing, quality, safety, operation and other departments, coordinated the parallel advancement of multiple r&d business lines, and formed an inter-regional, inter-center, and full-chain joint research team to go all out towards the goal of tackling the technological challenge.

the project team assembled to discuss the system design

"compared to the c3 system, new requirements were proposed for the new train control system such as multi-sensor fusion positioning, autonomous integrity inspection, moving block and ip-based train-to-ground wireless communication. not only did we face a lot of technical difficulties, but we also had to consider in advance the adaptability of the train control equipment to the western railroads, especially to the harsh climate of the desert area in xinjiang, which presented a real challenge. however, relying on casco's r&d strength and consistent craftsmanship accumulated in decades, we were determined and confident that we could complete this task," said zhou xin, deputy manager of casco's train control products, confidently.

the ruoqiang-hetian railway is located on the edge of the taklamakan desert, the second largest mobile desert in the world. about 2/3 of the line passes through the no-man's land in the desert where strong wind blows with sand all year round. it is extremely difficult for workers to station and maintain trackside equipment. therefore, the signaling system should be designed to minimize the trackside equipment and achieve remote centralized control at the station. "no track circuit was laid in the section, while train tracking was to be achieved, which was also a technical difficulty," said zhou xin, "we used wireless communication and introduced beidou satellite positioning to capture the position and movement of the train in real time and accurately, which also realized a leap of technology level from fixed block to moving block."

in 2019, the new train control technology design passed expert review and entered the stage of software and hardware r&d and experimental verification. in 2020, the on-board equipment prototype was successfully developed, and the software development of each subsystem was completed; in 2021, the type test and laboratory test were completed, and the expert test review was passed; in 2022, the interconnection test succeeded, and the isa safety certification was obtained... during this period, casco's technical team encountered many technical difficulties, and they overcame them one by one, living up to the expectations and accomplishing every step of the breakthrough.

by integrating casco's traditional superior products and the latest r&d achievements, the new train control system made important innovative breakthrough in the fusion of key technologies such as integrated train positioning based on beidou and on-board autonomous train integrity and safety inspection, and realized moving block train tracking. the successful implementation of this system not only means that china's train control technology will take a big step forward, but also realizes a major breakthrough in casco's domestic railway construction.

closed on-site test performed during the epidemic control

after the spring festival in february 2022, the ruoqiang-hetian railway entered the field test stage. the new train control system was to be finally tested on the ruoqiang-hetian railway, while many difficult challenges kept coming unexpectedly.

"the sudden outbreak was the first challenge we encountered", recalled cao dening, technical manager of casco. just after casco's vehicle test team arrived in hetian, the epidemic broke out in xinjiang, and the staff on site were required to conduct closed management for 7-11 days. after comprehensively considering the requirements of epidemic prevention and control and the test arrangement of the ruoqiang-hetian railway, casco's on-board equipment team simply started carrying out "closed-door preparation" on the train, testing in the locomotive room during the day, sleeping in the compartments at night, and eating three meals a day on the train. such hardship lasted for eleven days.

in addition to staying on the train 24 hours a day, the team members had to endure the small space in the locomotive room, noise and high temperature. sandstorms might break out at any time, so that people were often covered by dirt and sand.

sand everywhere outside the locomotive room

"the locomotive room was not completely closed. when the train was running and tested, i could see that the dust was blown into the locomotive room. at the end of a day, there was a thick layer on the equipment," said cao dening, "once, we needed to change the line interface of the on-board equipment, but we just couldn't find the identification of the wire terminal. it took a long time to find the plate which was buried under the dust."

left: dusty on-board technicians debugging on the train
right: identification plate of the wire terminal exposed after removing sand and dust

in this way, the test team experienced different days and nights in the desert. zhu yifei, participating in on-site work for the first time, still cannot forget his experience at the construction site of the ruoqiang-hetian railway. "the weather there often changed frequently in a day. you might experience frosty air in the morning, scorching sun at noon, blowing sandstorm in the afternoon, and dirty rain in the evening. it was really hard if we think about it now, but once the weather was pleasant, you could see the snow-capped mountains in the distance when you looked up. that was a holy and solemn moment, as if the mountains silently prayed there and protected our safety. that was probably a once-in-a-lifetime experience."

snow-capped mountains faintly visible in distance

new train control system successfully implemented after passing final test

since it is the first on-site application of a brand-new system, and the ruoqiang-hetian railway is also a special line for mixed passenger and freight transportation, in addition to the stability of the train control system itself, its cooperation with wireless communication, on-board equipment and other systems and its performance in extreme environments also required repeated verification.

"compared with the c3 system which uses circuit domain communication, the new train control system uses gprs packet domain communication. as it was the first time in the industry to use this mode for data transmission of the entire train control system, we encountered uncertainties at the beginning," cao dening said. in order to speed up the running-in and functional verification of the new system, in the early stage of the comprehensive test, the test team conducted intense operation tests to identify problems by accumulating more data and solve potential safety hazards, thereby enhancing the stability and reliability of the system operation.

operation test

"the daily operation mileage was 800 km back and forth, and the locomotive speed was fixed at 100 km/h, so gaining operation data alone took at least 8 hours a day," said li xiangyi who participated in the on-site comprehensive test of the ruoqiang-hetian railway. as li recalled, the process was far from smooth in the early stage. once, in a test running, the train suddenly braked abnormally halfway. after analyzing for a long time, they found that the gprs communication was interrupted, so they had to wait for the communication equipment supplier to fix it before starting all over again. "such small incidents kept happening, sometimes due to the equipment, sometimes due to communication, and sometimes due to our parameters that needed to be readjusted, so we were under great pressure in term of progress."

every morning before dawn, the field team had to start preparing for the tests of the day. after the operation tests in the evening, they would conduct a non-stop analysis and summary of the test data and make a plan for the next day. after these standard procedures, it was often late at night. "such work intensity tested everyone's body and mind. i often saw my colleagues around me sitting in the car without a place to lean on, and falling asleep with their heads hanging..." said li xiangyi with a bitter smile. "besides that, there were also many colleagues in casco's headquarters in beijing thousands of miles away who were concerned about the site, and they would stay up late every day, waiting to have meetings with us."

facing the morning glow& stepping on the moonlight

finally, after several months of on-site tests, all core systems passed the on-site tests and we reached a milestone of success. subsequently, the project team optimized and improved some system functions according to the needs of the client. in april this year, it successfully passed the on-site tests again, so that the new train control system was put into use as scheduled. "before the application of the new train control system, china's railway train control technology was generally dominated by the c2 and c3 systems, which put china in a place following and paralleling with international counterparts. now the new train control system has been applied successfully, indicating that china has begun to take over the leading position in the field of global train control technology," said xu xianliang with emotion, after the launch of the new train control system on the ruoqiang-hetian railway triggered a wave of heated discussions in the industry.

group photo of the project team

at present, casco is conducting more r&d for functional expansion based on the technical framework of the new train control system, and has completed the experimental test of the "beidou-based smart train control system" on the two freight railway lines, pingmei railway and jingbian-shenmu railway. in the next step, casco will continue to make technical breakthrough in automatic train operation (ato) on the basis of the new train control system.

many young casco colleagues devoted their first field mission to the ruoqiang-hetian railway, gaining themselves an unforgettable memory there. "there, you could feel the greatness of the previous generation of infrastructure builders everywhere. they built bridges in the desert, planted trees into forests, and applied drip irrigation to prevent sand. they constructed a real road in the place of death, and made everything impossible possible. they are the creators of miracles," said li xiangyi, "as a new generation of infrastructure builders, we, casco employees, can inherit the career of our predecessors and become one of the thousands of builders of the ruoqiang-hetian. this is the most precious honor in itself.”



11f, building 2, shibei one center, no. 21, lane 1401, jiangchang road, jing'an district, shanghai

86 -21-5663 7080

© 2019 casco signal ltd.. all rights reserved.