Passengers play cards on the train from Jilin to Tumen in Northeast China's Jilin province. [Photo by Qu Xiaoxi for chinadaily.com.cn]

Doubao, a sticky steamed bun stuffed with sweetened bean paste, is a popular snack in northeast China, but now few know how to make it.

Tian and his wife usually prepare 400 kilograms of doubao every winter and sell them in nearby cities, which can earn them about 3,000 yuan ($435.4).

"That's thanks to this slow train that takes us outside," he said. "The extra income can be used for Spring Festival and spring plowing."