The Vibrant Express trains, running between Hong Kong and other destinations in Guangdong province, made their maiden journeys to the mainland from the swanky, newly-built West Kowloon Station at 7 am on Sunday.

Hailing it as "the fresh beginning of a new life", Secretary for Transport and Housing of the Hong Kong Special Administrative Region Government Frank Chan Fan said the new rail line is a cross-boundary infrastructure mega-project that "every Hong Kong resident should take pride in".

"Mooted in 2000 and more than eight years in the making, the 26-kilometer project comes as an extraordinary and meaningful birthday gift for the country's National Day on Oct 1," Lam said at an event on Saturday.

"It makes a well-timed debut when the world's second-largest economy commemorates the 40th anniversary of the ground-breaking reform and opening-up policy this year, and offers an historic opportunity for Hong Kong people to see for themselves the economic, social and technological development miracle on the Chinese mainland," she said

The transportation link, with a cost of about HK$84.42 billion ($10.8 billion), is operated by the city's sole train operator, Mass Transit Railway Corporation. It stands as Hong Kong's first-ever high-speed train that will slash travel time to Guangzhou by more than half to 47 minutes, and connect passengers from Hong Kong to 44 destinations on the Chinese mainland, including Beijing and Shanghai.