CHANGCHUN - China has developed a bullet train that can convert its sleeping berths to seats to meet demand for around-the-clock operations, a train maker said Monday.

CRH5H, China' first high-speed sleeper train cars that can operate at high altitudes and in cold weather, as well as windy and sandy environments, is unveiled in Changchun, Northeastern China's Jilin province, on Nov 11, 2016. [Photo/Chinanews.com]

Nicknamed "Panda" because of their black-and-white nose design, two CRH5E trains came off the assembly line Friday at the CRRC Changchun Railway Vehicle Co. in Changchun, capital of northeast China's Jilin Province, said a manager with the company.

Among the 16 carriages on the trains, 13 of them are equipped with compartments with both seats and beds. The beds for night operations can be folded in to seats during the daytime, the manager said.

CRH5H, China' first high-speed sleeper train cars that can operate at high altitudes and in cold weather, as well as windy and sandy environments, is unveiled in Changchun, Northeastern China's Jilin province, on Nov 11, 2016. [Photo/Chinanews.com]

Passengers in the compartments have access to WiFi and can charge their electric devices with installed sockets or USB ports.

With a maximum speed of 250 km per hour, the trains can run in temperatures as low as minus 40 degrees Celsius.

Sound proofing and vibration damping can reduce noise inside the carriages to 65 decibels when the trains run at maximum speed, a noise level suitable for conversation, the manager said.