Xu Mingze assembles the 3D printer in Chongqing, Nov 23, 2016. [Photo/VCG]

Xu Mingze is a machinist studying 3D printing technology to repair any faults in high-speed trains in Chongqing. Xu, a 20-something, began searching online for documents that could help him print model parts of trains in 3D. After studying the model parts, he and his colleagues could figure out the internal structures of the trains that would help them repair or improve trains in the future.