Shi Jin is a highly skilled doctor of sorts, but his patients are not human — they're electrical equipment.

"Equipment, like people, can get sick. Maintenance is like providing regular physical examinations. It must not be sloppy," he told his fellow wiremen, who were eager to learn from him on Friday at a power substation in Lanzhou, Gansu province.

The substation powers the rails, which in turn power the electrical Harmony locomotives on the line.

"Like a human heart, power supply equipment sustains the great arteries of the railway. The system cannot operate if the heart is diseased," said Shi, an assistant engineer at the Lanzhou power supply section of China Railway Lanzhou Bureau Group.

Over the past 27 years, Shi, a national railway model worker, has made more than 20 scientific and technological innovations, handled more than 1,000 electrical faults at substations and removed more than 800 hidden hazards.

He still remembers the hard times when he started working at the Shengou substation, located along the Hexi Corridor, the main artery of the ancient Silk Road.

"It lacked residential facilities. We could not take showers or watch TV. We had to go more than 5 kilometers to buy vegetables in a nearby town," he recalled.

Despite the arduous conditions, Shi solved dozens of technical problems.

The internal mechanics of electric switches and circuit breakers might change with low temperatures in winter, resulting in on-off failures from time to time. Shi developed a way to solve the problem, and his method was adopted in 28 substations in Lanzhou, saving more than 1.8 million yuan ($277,740).

"Now, our working environment has changed dramatically and the quality of equipment is much better," said Shi, adding that he hopes the young wiremen can carry on the traditions of their predecessors.

Shi believes that to ensure the safety of the power supply, it must not depend solely on one person's technical skills. A team of professional, highly skilled workers is required.

He has been sharing his experience with the younger ones. With Shi's help, 16 wiremen have become technicians and technical experts.

Huang Shuting contributed to this story.