For Yu Jiangchong, 49, this year's Spring Festival rush may be his last on train. Human train guards are now obsolete, and been superseded by technology. "Thirteen of us have been transferred to other posts. I'll be lucky if I see out the year," Yu sighs. Yu has spent 26 years serving as a train guard at the Datong City section of the Taiyuan Railway Bureau, in north China's Shanxi Province. His job is ostensibly to "monitor train operations" and be prepared for emergencies, all the while sitting alone at the train tail. When his train passes through stations, he signals with red and green flags to drivers and station staff. He can also access the train's breaks and stop the train if necessity demands. He remembers the only time he had to pull the brake was in 1995, when he found a carriage door of the running freight train had opened. "The door belt possibly got loose when the train was running," he said, adding the open door flapping at the side of a speeding train could have caused untold damage to the signalling gear along the track. "If the signal gear had got damaged, train operations all along the line would have been badly disrupted. The consequence would have been very serious," he said. Yu believes his job has been very important in China's railway cause, but with the national train revolution, guards are being phased out. Zhi Xiquan, director of the Datong section, said that the number of guards working on the section had decreased from more than 300 to a mere 50. "Technology is the main culprit," he said. Railway construction in China has gone at breakneck speed over the last ten years. There are now more than 12,000 kilometers of high-speed lines with bullet trains running at up to 380 km per hour. At that kind of speed, keeping the train safe with nothing more than the guards' naked eyes is impossible and electronic systems must do the job instead. More and more guards have been given new jobs, and the remaining 6,000, including Yu, will leave their posts when "end of train devices" are installed on all passenger trains later this year. Their other tasks -- safety checks before train starts moving and air pressure reporting -- have been distributed among station staff and train stewards. "The device is still being tested, but it will soon replace us," he said. Yu worries that technology can not cover his job. "What if the device breaks down? What if there is an unforeseeable emergency along the way? Unexpected cases have to be dealt with by people," he said. Yu's concern is reasonable. In July, 2011, 40 people were killed in Wenzhou when two bullet trains crashed into one another. The crash was caused by a series of flaws in control systems and made worse by the inadequate emergency response of railway authorities. "Human guards aided by devices are the best way to ensure safety," Yu said.