In the Taihang Mountains region of northern China, a unique transport known as the "Train of Happiness" traverses the rugged terrain.

Officially designated as a public welfare "slow train", the 8818/8817 conveyance is operated by the China Railway Taiyuan Group. With its affordable fares and convenient services, it's a favored choice for locals.

Stretching 305 kilometers, the ride costs as little as 4 yuan (58 cents) at its lowest fare and 34.5 yuan at its highest. Many of its stops are conveniently located at the very doorstep of villages, making it an essential part of daily life for many, including 71-year-old Liu Ronghua from Lingqiu county in Datong city, Shanxi province.

Liu, who helped build the railway in his youth and later worked on bridge maintenance for three years, is a frequent passenger. "Thanks to the public service train, we can venture beyond the mountains and see the outside world," she said.

The longest-running public welfare slow train in the province operates on the Beijing-Taiyuan Railway, traveling from Taiyuan Station to Lingqiu Station in seven hours and 30 minutes at an average speed of less than 45 km per hour. There are 34 stops along the route.

Since its inception in 1991, "The Train of Happiness" has made daily round trips, weaving through historical sites such as Yanmen Pass and Mount Wutai, effectively linking remote villages with bustling urban centers.

For Sun Zhibin, a teacher at Lingqiu No 7 Middle School, a ticket purchased in 2002 changed his destiny. Carrying a woven bag and wearing plastic-soled shoes, he boarded the train to Taiyuan for his studies. The 19.5-yuan ticket was a precious sum, saved from his father's frugal earnings. On that journey, Sun met his future wife, and after graduation, they returned to Lingqiu. Now, he often takes his children on the train, retracing the path of his educational journey.

Students are a common sight on the "slow train". Sun Nan, a master's student at Shanxi Agricultural University, frequently travels home with agricultural technology materials in hand. His research on livestock has significantly increased the lambing and survival rates of sheep in his hometown, doubling his family's income.