When Li Renchao became a train engineer in 1959, he did not think it would become a family affair. Both his son and grandson have worked for China's railways, reflecting the country's development from steam power to internal combustion and finally electric engines.

Li, now 81, started work with the Lanzhou-Xinjiang Railway in 1959 as a 21-year-old trainee. He then became an engineer operating steam engines, which were notorious back then for their slow pace, shabby interiors and lack of air conditioning and sleeper beds. All this was accompanied by plumes of black smoke.

"The conditions were not what people would accept for a normal job these days," he said. "The steam locomotive needed people to add coal without a break. A 200-kilometer journey needed 10 tons of coal, so stokers were adding coal all the time."

In winter, with temperatures at-20 C, icicles could be seen hanging from the roof of the engineer's cabin. Even the proximity of the coal furnace did not help. But in summer, hot days were insufferable.

His son, Li Wen, has an enduring memory of his father's face covered in soot after work. Despite hearing countless stories from his father about how to handle hunger, cold and heat - and even sometimes having to repair the train - he followed in his footsteps without a second thought.

"Forty years ago, a train with a speed of more than 40 kilometers per hour was the most efficient transportation on the Qinghai-Tibet plateau. So being a train engineer was an extremely honorable thing for a family," he said.