A new high-speed train service between Hong Kong and mainland China will open this weekend, but it's bringing more than passengers to the former British colony.
New rules passed by the Chinese government will allow authorities to enforce Chinese law at the Hong Kong station used by the super trains.
Opponents of the new law say it's unconstitutional and sets a dangerous precedent for Beijing applying mainland laws in Hong Kong.
Hong Kong does have governmental separation from the mainland. It's run as a 'special administrative region' essentially a 'one country, two system' approach.
An appeal against the new law will be heard in the high court in October, after the service has launched.
However authorities are moving full steam ahead and everything is on track for the train's first journey on Sunday.
Travelling at more than 300 kilometres an hour, the trains will provide an alternative to air commuters between Hong Kong and some of China's main cities.
The new service will operate between Guangzhou, Shenzhen and Hong Kong via a 25,000 kilometre railway line. The journey time between Hong Kong and Guangzhou will be just 48 minutes.
To put that speed into context, if the train were to operate in New Zealand, it would be able to travel between Auckland and Wellington in just over two hours. It could travel from Kaitaia to Bluff in less than seven hours, and between Britomart and Henderson train station in Auckland in three minutes.
The new rail link cost more NZD$92 billion to build.