All six 25-minute episodes of the Chinese documentary The Slow Train Home are scheduled to be aired on the Documentary Channel of China Central Television （CCTV） from October 22 to 27， 2018.
　　Choosing the once-ubiquitous slow green trains as the theme， the documentary explores traditional customs of old Chinese villages， vanishing traditional skills and the historic changes that have upended centuries-old lifestyles. At the same time， such images inspire a strong sense of nostalgia in people across China.
　　Nostalgia is at the core of this documentary. “When taking the slow trains， people could see mountains and rivers along the routes， which left them with more vivid memories and accompanying nostalgia，” said Ren Chongrong， producer and project supervisor of the documentary.
　　Mass migration is a normal phenomenon in human development history and has frequently been a powerful driving force for social progress and prosperity. China’s current urbanization process has been dubbed the largest population migration in human history. Countless people have left their ancestral homes to establish new residences in cities. Meanwhile， nostalgia has exploded as a popular emotion among the public.
　　The slow train， the most common and representative vehicle for long trips in China from the 1950s to the 1980s， carries the nostalgia in the production. The trains are painted green with yellow stripes and lack centralized power and air conditioning. They are designed to reach a maximum speed of only 120 kilometers per hour.
　　With the rapid development of the Chinese railway sector and the constant upgrades in speed and technology of passenger trains， most of the slow trains in the country have been gradually replaced by newer bullet trains with air conditioning， electricity and higher speeds.
　　The documentary production team discovered during pre-production investigation that only about 20 lines and 40 total slow trains still operate in China today.
　　The still-familiar slow trains are fueled with coal， lack air conditioning and feature famously hard seats. However， these “stars”of the documentary still maintain two important advantages over their faster competitors： Tickets are cheap and many stops are made， so for some， the trains remain an indispensable method of transport.


　　Since the beginning of 2018，the production team had ventured to many places in China including Sichuan， Heilongjiang， Hunan and Shanxi provinces and Xinjiang Uygur Autonomous Region to gather footage. 　　Backdrops include the snowcapped Daliang Mountains in China’s southwestern Sichuan Province， the forested Hinggan Mountains in China’s northernmost Heilongjiang Province， the magnificent Tianshan Mountains and Taklimakan Desert in China’s northwestern Xinjiang Uygur Autonomous Region as well as small towns along the border of Sichuan and Hunan provinces.
　　From The Palace Museum（2005） to The Forbidden City 100（2012）， China （2013）， Custom-made for Life （2016） and finally The Slow Train Home （2018）， Ren’s documentaries have gradually shifted from grand themes of history and culture to intimate portraits of ordinary people. She believes that stories of ordinary people in the context of a great era can be some of the most touching and attractive such as kids going to school by train， orange vendors， and a bride from the Yi ethnic group， featured in The Slow Train Home.
　　Ren added a poetic and warm touch to her latest work. “Today， thanks to the popularization of high-speed rails in China and so many young people moving to the cities， slower lifestyles and traditions associated with the few remaining slow-speed green trains have become a kind of humanistic concern we hoped to kindle through nostalgia，” she explained.