'Mobile bazaar'
Opened to the public in 1970, the trains travel between Puxiong township and the city of Panzhihua, covering 376 km in 11 hours at a speed of less than 40 km per hour, with 26 stops along the way. The fares range from 25.5 yuan ($3.8) to 2 yuan.
In the past, the couple eked out a meager income by toiling countless hours in the fields. In 1985, her husband died of a pulmonary disease, leaving Layi and their three sons to fend for themselves.
Following her husband's death, Layi set up a modest grocery store to sell daily necessities and shuttles between their farmland and the store to sustain herself.
On weekdays, she takes the 5633 train from Mianshan to Xichang city to replenish stock at a wholesale market. And on weekends, she takes the 5634 train in the opposite direction to run a stall at a fair in Nibo township.
Layi, a regular commuter, lauds the railway service for its cost-effectiveness.
She says that the road from Mianshan to Xichang stretches about 72 km and making a round trip by bus is quicker, but it would cost 80 yuan. Though the round-trip journey by slow train takes about three hours, it only costs 10 yuan. The 70 yuan saved on the fares is the same amount as her store's net profit for a day.
The train is not just a mode of transportation for local residents, but also a "mobile bazaar".
Locals are encouraged to bring their farm products on board and trade the goods while commuting. To facilitate their journey, two rows of seats at both ends of each carriage have been removed, so that they can pile up their baggage and place their livestock and poultry.
For Yihuo A'niu, a ninth grader, the train is like her school bus.
Every Friday afternoon, she boards the homebound train, together with her 700 or so schoolmates. The 140-km journey takes about four hours, but she can always find a way to break up the monotony by reading books, doing her homework and chatting with friends.
Yihuo was scheduled to take this year's senior high school entrance exams beginning on June 13.
"I want to be admitted into the best senior high school in Liangshan, and become a good teacher or a brave police officer in the future," she says, adding that she aspires to explore the vast world beyond the mountains.