Today, turning on a tap to access clean running water has become part of everyday life. Yet along the Qinghai-Xizang Railway, the domestic water for workers at many stations depends on a special "dedicated train" for delivery.

This train carries no passengers, and its sole mission is to deliver domestic water. Nor does it have a fixed schedule; whenever passenger or freight trains pass by, it must pull over and wait. That is why it is affectionately called the "Eighth-Class Train." Modest as its name may sound, its core mission -- guaranteeing water supplies for frontline railway staff -- is far from trivial.

Zhang Zhongyou, now 53, is one of the "water suppliers " who have spent years shuttling between water-scarce stations along the Qinghai-Xizang Railway, bringing fresh water to frontline workers.

Water for daily life on the “bottom-class train”

The train arrives at Dabson Station.

Located deep in the Qaidam Basin, Dabson Stationn is surrounded by vast stretches of white saline-alkali land where nothing grows. The groundwater has such high salinity that even boiled water leaves a white scum on the surface. So all the drinking and domestic water for the station staff must be hauled in from Golmud.

Each "bottom-class train (Eighth-Class Train)" has 8 water tanks, with a total capacity of 600 tons of water in one trip.

Zhang Zhongyou gets off the train, walks to the end of the water tanker, squats down to inspect the water pipe. He runs his fingers along the pipe all the way, checking for cracks at the joints and aging of the rubber rings. When he feels a rough spot, he scrapes it twice with his nail and continues running his hand down the pipe. After finishing the inspection, he wraps the pipe nozzle with a dry cloth before tucking it into the fixed bracket.

Half an hour later, all the water in one tanker is drained. He pulls open the door and jumps onto the train, then pokes his head out to double-check the water tank valve. Only after confirming it is tightly closed does he pull the door shut and return to the carriage. After years of bending over to work, his back is more hunched than most people of his age, with his shoulders slightly tilted forward. "It's bearable now. Winter is the real test," he says.

On days when the temperature drops to minus 20 degrees Celsius, the iron carriage is like an ice cellar, and the boiler has to be kept burning nonstop. In the past, he had to get up every two or three hours at night to add coal -- if he didn't, the water pipes would freeze. Wrapping himself in a thick cotton-padded jacket, he would climb out of bed in the middle of the night, squint and shovel two shovelfuls of coal into the furnace. The flames would leap up, warming his face for a moment, but as soon as the fire died down, the chill crept back up from his feet. "Now we've switched to oil heating, which is much more convenient."

The most strenuous part is draining the water. "As soon as water flows out, it freezes at the joint, and the ice keeps getting thicker," he says. He squats beside the pipe and keeps a close eye on it. When the ice builds up, he knocks it off with a pickaxe -- the ice forms again after being knocked off, and he knocks it off once more. Draining water at one station takes at least one or two hours. When his hands go numb from the cold, he tucks them under his armpits to warm them up, and goes back to work as soon as they thaw.

Once, the outlet pipe was completely blocked by ice. Zhang Zhongyou crawled under the train, lay on the gravel ground and poured boiling water on the pipe nozzle. By the time the ice melted and the water trickled down, the knees of his cotton-padded trousers had frozen into a hard shell. His legs could not bend, and he had to shuffle along little by little. He patted his trouser legs and said with a smile, "if I take them off, they can stand upright on their own." The back of his hands are bluish-purple, with dark red cracks on the unhealed frostbite.

Two hours later, the dispatching signal arrives, and the train slowly starts moving. The next stop is Nanshankou.

The black mosquitoes at Nanshankou Station

The black mosquitoes at Nanshankou Station are extremely vicious.

When Zhang Zhongyou unloads the pipe from the water storage tank's water inlet, he gets bitten on the back of his neck again. He raises his hand and slaps his neck, leaving a small dark-red smear on his palm.

"These mosquitoes are tiny and black. They bite without making any noise. By the time you feel the itch, they've already sucked their fill of blood," he says. One bite will leave a swollen, itchy and painful mark that won't fade away for three or four days.

"Got bitten again?" A voice comes from behind. It's Li Yongliang, the station master of Nanshankou. Holding an anti-mosquito spray in one hand and a thermos flask in the other, he walks over from the opposite side of the water well. "I'm used to it," Zhang Zhongyou says, taking the spray and spritzing it on his neck. "These black mosquitoes are just like us -- old friends we've known for years." Li Yongliang chuckles and puts the thermos on the platform edge, then hands it over. "Everyone has been waiting for you for days."

"The 'Eighth-Class Train'," Li Yongliang repeats the nickname,"last week we waited for your train from the afternoon until it got dark."

"Aren't we exactly 'eighth-class'?" Zhang Zhongyou says. "When there are no other trains on the line, we're a 'special train'. When there are, we're the 'last one'."

The scent of milk tea in the carriage

Xitieshan Station is located on the northern edge of the Qaidam Basin, with not a single household visible for dozens of miles around.

The drinking water for the dozen people working at the station also relies on Zhang Zhongyou's "Eighth-Class Train".

That day, after finishing draining the water, it was already past noon. Zhang Zhongyou pulls out a cardboard box from under his bed -- its corners are worn and fuzzy, and inside are the things his son prepared for him: several boxes of instant noodles and a few cups of milk tea. Every time before he sets off on a trip, his son quietly restocks the box.

"The boy has grown up and knows how to care for others!" Zhang Zhongyou says with relief,"I told him we have everything we need on the train, but he still worries."

Once, he found a note tucked in the box, written in his son's handwriting: "Dad, remember to eat on time."

"The kid is more nagging than his mom," Zhang Zhongyou says, the corners of his mouth turning up in a smile. The smile deepens the wrinkles on his face, looking exceptionally vivid in the dim light of the carriage.

His son's thoughtfulness is learned from his mother. Zhang Zhongyou's wife used to be a frontline track maintenance worker on the Qinghai-Xizang Railway. They worked on the same line -- one patrolling the tracks, the other delivering water. It was normal for them to see little of each other. A water delivery trip would take three to four days or even a week. When he got back to Golmud for a break, his wife was often still out on the line. When his wife got home for rest, he had already set off again.

Now his wife is retired, but the care has passed to their son. Before every departure, the son stuffs the box with instant noodles and milk tea, while his wife folds his spare clothes and leaves them by the door. As soon as the train pulls out, that cardboard box travels with him -- carrying the warmth of the home he has to leave behind.

The sun dipped low in the west, its afterglow lighting up the windows. After finishing the day's water-delivery work, Zhang Zhongyou returned to his bunk, bent down to glance at the box underneath, and then gazed out at the vast, desolate plain stretching into the distance.

Reporter: Xue Ying

Translator: Luo Rongting, Zhi Xinghua

Review: Phurbu Tsering, Drakpa Wangchen