A long stream of trains and trucks are bringing in much needed supplies to the roof of the world, as winter sets in. But the long train journey of 30 hours at 4000 meters above sea level is never easy.

Specially trained freight train operators are needed to make this arduous journey. The second section of the Qinghai-Tibetan railway starts from Golmud in Qinghai province and ends at Lhasa in Tibet. Currently there are only 175 train operators who make the journey.

Fan Hongxing, a freight train operator is one of them. He will take shifts with his colleagues during the 30-hour journey, much longer than the regular passenger trip. The control room of the train is nothing special, except for its oxygen generator.

Fan Hongxing said, "We’ll get as high as 5000 meters above sea level in the mountain area and we have to inhale oxygen all the way. There was one time when the oxygen generator stopped working, I felt a sharp headache, I had to press my head very hard. I was suffering."

Fan Hongxing has every reason to worry especially when the train passes the Tanggula Mountain, the highest area during the entire journey. Sitting at an altitude of 5200 meters, it's hard for drivers to get a good night sleep even with the extra oxygen. In fact, most of the 175 train operators have suffered from altitude sickness.

Fan Hongxing said, "My father knows the difficulties of my work because he was also a train operator before retiring. He reminds me to be safe but he never asked me to change my job. He understands me."

Families not only provide moral support, but a hearty cooked meal as well. The wives of manyoperators prepare food for their husbands, to eat on their journey. Despite the goodwill from their families, their long hours have left them unable to take their loved ones on the trip.

Fan Hongxing "I feel bad that I haven’t brought my wife and child to Tibet even once. I really want to. I hope one day I can have them on my train and hearing my wife proudly telling others the driver of this train is her husband."

Fan Hongxing has been working on this line for five years. He is proud to be among the 175 train drivers working on the highest railway in the word. He believes that Tibetan people will not forget their contribution to the region.