Hong Kong's controversial bullet train got off to a smooth start Sunday, as hundreds of passengers whistled north across the border at speeds of up to 200 kph (125 mph), deepening integration of the former British colony with mainland China.

While the $11 billion rail project has raised fears for some over Beijing's encroachment on the Chinese-ruled city's cherished freedoms, passengers at the sleek harbor-front station were full of praise for a service that reaches mainland China in less than 20 minutes.

"Out of 10 points, I give it 9," said 10-year-old Ng Kwan-lap, who was traveling with his parents on the first train leaving for Shenzhen at 7 a.m.