For Zhong Junlan, taking the helm of a China Railway Express train is like running a relay race. "I drive to point A," he said, "and then another driver takes over, then another, and so on, until the cargo reaches its final destination."

It is a race he has been running since 2013, when he was chosen to drive the first leg of the inaugural cross-border freight service from Chengdu, the capital of Sichuan province, to Lodz in Poland.

The journey to Guangyuan, 360 kilometers up the track, takes on average more than five hours, he said. From there, about 50 drivers will steer the cargo in shifts the rest of the way, some 9,466 km, over about 12 days.

For safety reasons, drivers in China are restricted from working for more than six hours at a time. Zhong said if a CR Express train is scheduled to pass through Guangyuan in the opposite direction within a day or so, he will drive that back to Chengdu. If not, he will take a day off and return to base for his next assignment.

Although the 33-year-old is a veteran in starting the race, he has never seen the finish line.

"It's a pity that I've never been to Alashankou," he said, referring to the city in the Xinjiang Uygur autonomous region where the train crosses the border into Kazakhstan, "or to Lodz, for that matter."

Zhong's role may only cover 4 percent of the entire journey, but he said the job is far from easy.

"It's a mountainous region between Chengdu and Guangyuan, with many ups and downs and curves. So it requires extremely smooth handling to drive a CR Express train because it can be carrying fragile or valuable commodities, such as electronic products, handicrafts or plants," he said.

The maximum speed a freight train is allowed to go in China is 120 km/h, although Zhong said he takes it slow.

"I have been driving freight trains on this stretch of track since 2009. I know every corner and every hill," he said, adding that experience has taught him when to adjust the speed to keep a train steady depending on its length and weight.

Since the first rail freight service left Chongqing in 2011, the number of international freight services has risen rapidly. So too has Zhong's workload. "When I first started to drive freight trains, it was less work, as there were only a couple of trains a week. Now, one to three trains leave Chengdu every day," he said. "We also used to have fewer drivers, and we worked on other assignments. Today, CR Express drivers only take the helm of CR Express trains.

"My dream is to one day take the train all the way to Alashankou, or even Lodz, to see the changes our services bring to locals along the railway," he added.