LONDON, May 21 -- The Heathrow Express, which links downtown London and Heathrow airport, on Wednesday temporarily renamed itself the "Chengdu 72 Express."

Some carriages of the train have been decorated with adorable giant panda patterns to make more people aware of the 72-hour vise-free travel policy designed to attract more travelers from Britain to Chengdu, capital of southwestern China's Sichuan Province.

Promotional films on the city will be showcased on the train until Friday.

As the giant panda's home and a vital transportation hub in southwestern China, Chengdu is the fourth city in China to launch the 72-hour transit visa policy last September.

Under the policy, foreign transit passengers from 51 countries who hold flight tickets to a third country can stay in the city for 72 hours. In 2013, direct Chengdu-London flights were also introduced.

"Two weeks ago, the weekly number of the flights have been increased from three to five, which has greatly shortened the distance between Chengdu and London," said Li Li, deputy director of the Chengdu Municipal Foreign Affairs Office.

"We hope through Heathrow airport and through the Heathrow Express, British people and citizens of London will know more about our city, and will go to Chengdu for business, tours and study," she added.

"Chengdu is the only city in China doing campaigns like this. It's quite unusual and we've never done this before. I think they will like the design," said Simon Evans, head of communications of Heathrow Express.

The promotional activities are part of the "2014 London Chengdu Week," launched on May 19. A Chengdu-style teahouse will be held in Covent Garden between May 22 to 25 where people stand the chance to win free 72-hour trips to Chengdu.