So far, Last Train Home has shown in 19 cities, and Fan plans to continue his tour.

Professor Zhang Tongdao from Beijing Normal University's School of Art and Communication says Fan's promotional format is courageous.

"It needs to pass the test of time, but such an initiation is worthy of admiration," Zhang says.

Fan says his decision to shoot a documentary about migrant workers arose from his feelings of social injustice.

Fan has focused his lens on migrant workers.

A former journalist and cameraman for CCTV, he often went to remote areas and was shocked by the difference between life for those who lived in rural areas and in the rich cities.

"The kids in rural areas lack parental care. Why? Because their fathers and mothers are mining and housekeeping and washing plates in big cities," Fan says.

"The migrant workers are exploited for urban modernization, but they still live in the cracks of society and lack respect."

He chose the Spring Festival migration because it was an ideal subject to trace the effects of long-term separation on migrant workers' families.

"The documentary was intended to establish a monument to the backbone of the country. Migrant workers deserve recognition."

When filming the documentary in Guangzhou in 2008, Fan was squashed by crowds scrambling to get on the train at Guangzhou railway station.

"It was snowing, and the people were jostling, crying and cursing. People stepped over those who had fallen, to move forward, and there was no dignity to the occasion at all," he says.

"All this happened because they wanted to return to their hometown and see their children and other family members."

Fan says he focused his lens on just a fraction of the tens of millions of migrant workers in China that regularly overwhelm the country's rail system.

"The documentary is so heavy that it would be a shame if our countrymen cannot see it in cinemas," he says. "That's why I spared no effort in pushing the film on the big screen."

Fan's latest project centers on the second generation of migrant workers and is currently in the casting stage.

Fan will also produce a documentary that records how rural teenagers become boxing champions.

"And then, I will begin the next round of my screening odyssey," he says.

Contact the writer at sunli@chinadaily.com.cn.