1 / 6   Guangdong-Hainan Railway, or Yuehai Railway, is the first cross-sea train route in China. It operates from the city of Zhanjiang in southeast Guangdong Province to Sanya, the most southern city in Hainan Province, crossing the Qiongzhou Strait in the middle. /VCG Photo

2 / 6   But how can a railway connect the separate land masses? It’s all thanks to the train ferry – a ship that can carry both freight and trains across the strait. Yuehai Railway Ferry No.1, the first train ferry put into use on the Yuehai Railway, entered service in 2003. /VCG Photo

3 / 6   To ensure the train can enter the ferry smoothly and properly, the tracks on both land and ship must be perfectly aligned — a tricky task given the constantly changing sea level. A control room carefully monitors the sea level and controls the height of the tracks. /VCG Photo

4 / 6   Upon arrival at the ferry terminal, the train is divided into three to five sections and pulled on board the ship by a locomotive. It usually takes around 30 minutes to arrange and fix the carriages on the ferry. /VCG Photo

5 / 6   During the 30-minutes process, the power supply is cut off and only returns when the carriages are secured on the ferry. Passengers remain on the train during the one-hour journey to the port on the other side. On arrival, the carriages are reconnected on the land-based tracks and the train heads towards the final destination. /VCG Photo

6 / 6   The establishment of Yuehai Railway has not only strengthened economic ties between the mainland and the island province, but also boosted tourism in Hainan. And the route has developed quickly over the past 15 years, with four train ferries now in service. /VCG Photo