It wouldn't be possible for China to operate some of the world's fastest trains, traveling at the speed of up to 350 kilometers per hour, without maintenance teams working their fastest through the night to keep the trains going uninterrupted.

Since these trains operate as per tight schedules, maintenance crews have only about four and a half hours, sometimes even less, to accomplish their task. And there is a lot to be done: from monitoring the tracks to polishing the rails that helps trains run fast and smooth, from checking miles and miles of cabling to thousands of screws and hundreds of other components. It's the job they have to do night after night on time and without fail.

CGTN visited the team working at Cangzhou Bullet Train Railway Maintenance Center. From this remote part of central China's Hebei Province, maintenance teams are dispatched along the lines between Beijing and Shanghai, preparing the tracks and the trains for their next day at work. 

There are around 200 staff members at this maintenance center, most of whom are engaged in physically challenging work. Each person has to walk up to six kilometers every night, even bend over while walking to ensure no damage to the tracks.

Zhang Jun is one of those performing this demanding work. He has been working here for 30 years. "To be honest, it is a very tough working environment, but I really love this job, especially because I get a chance to work for China's bullet trains. I feel very pound, which makes me forget the hardships of this job," Zhang told CGTN. Zhang is the third generation from his family to work for the railways, so he was born and brought up in a community close to the tracks. 

More than simply being a part of his life, it's his passion. Two years after bullet trains were first introduced in China, Zhang started his services, learning more from German engineers like how to polish the tracks using machines. He went on to become the first Chinese to master the technique. Since then he has passed his skills to many newcomers.

China has the world's longest high-speed railway network spanning 29,000 kilometers with more than 2,872 trains, and Zhang is just one of the many who work all night to help the passengers and the nation reach their destinations.