In addition to being a colleague and the head conductor of the No 57031 train, Zhang Menghe is also a friend to those working or living alone the route of the Linhe line.

He and his two colleagues deliver daily necessities to the 25 stations and six desertification control stops along the train's route, bringing goods, water and tools to the remote region.

Connecting Linhe station in Bayannuur city in the Inner Mongolia autonomous region to Hami station in the Xinjiang Uygur autonomous region, the line runs for over 1,390 kilometers and serves as a gateway linking Northwest China and Inner Mongolia.

It crosses three deserts along the way－the Badain Jaran, the Ulan Buhe and the Yamarek－and the 57031 is the only source of water for those working at desert stations.

Unlike high-speed trains, Zhang's train, which runs from Linhe station to Mazongshan station in Gansu province, travels at an average speed of just 35 km per hour.

Its main function is to transport goods and personnel.

Zhang and his colleagues leave Linhe every Monday morning, arrive at Mazongshan on Wednesday morning, and return to Linhe on Thursday. Travel times vary, but a round-trip can take up to 90 hours.

"I started to work on the Linhe line when it begun operations in 2005," said Zhang, 59.

"Since 2017, I've worked on No 57031. I do just over 50 return journeys between Linhe and Mazongshan each year."

On Oct 18, a few cases of COVID-19 were reported in Ejine Banner, Inner Mongolia, and public transportation in the region was suspended to prevent the spread of the virus.

Zhang was told that he and his crew were needed to deliver face masks, protective suits and disinfectant to the virus-hit areas.

"When I was given the mission, I knew it would be impossible to go home until there were no more new cases, so I was physically and mentally prepared to live on the train," Zhang said.

Before the first trip, which was slated for Oct 25, Zhang made arrangements regarding family business with his wife, something he'd normally take care of himself during the three days he has to spend with family between trips to Mazongshan.

"My wife lives in Bayannuur, and my daughter and two granddaughters live in Baotou (in Inner Mongolia). With me being away, I had to rely on relatives to look after them in case of an emergency," he said.

Concerned about those who lived along his route, Zhang responded happily to requests for fresh vegetables, rice and medicines.

At 8 am on the day they were first due to depart, Zhang and his colleagues began loading supplies and other items requested by residents along the line.

"The three of us had to load 16 metric tons of supplies and make sure not to confuse which packages needed to be offloaded at which station," he said.

They also sterilized everything three times before departing.

"It felt like a layer of your skin was being stripped off. I was sweating when we were loading the supplies, but I felt our efforts were worth it when people were able to get the things they urgently needed on time," he said.

Zhang kept a to-do list, in which he recorded the names of the people and the things they needed.

"He has a kind heart. Every time I called to ask him to bring things to our station, he never refused. He even brought us the food he'd cooked himself. We all appreciated his help," said Hou Peng, head of Tuodichuan station along the line.

Early on Nov 29, Zhang disinfected his train with a smile.

After 35 long days on the No 57031, this was the day that he and colleagues would finally be able to go home and see their families.