On December 30, 2019, the Beijing-Zhangjiakou high-speed railway officially began operation, becoming the world's first intelligent high-speed railway running at 350 km/h with driver-attended automated driving.

In parallel, intelligent driving in road transportation is also accelerating rapidly in China. According to Wang Shuiyin, vice president of the Research Institute of Highway under the Ministry of Transport, the country's penetration rate of intelligent driving passenger vehicles has exceeded 68%, and the total length of open testing roads for autonomous driving has surpassed 28,000 kilometers.

However, despite both belonging to intelligent driving, rail and road systems differ fundamentally in complexity and operating environments.

"The gap between automotive and rail automation is significant," Wang Xiaoliang, vice president and chief engineer of Beijing Hollysys Co., Ltd. under the Hollysys Group, told CGTN.

"One of the core challenges is precise stopping," Wang said. "Due to environmental variations, parameter deviations and massive real-time data transmission requirement, achieving this in high-speed rail is extremely difficult."

Unlike road vehicles, high-speed trains operate under tightly controlled conditions at extreme speeds, where even minor deviations can have amplified consequences.

Wang explained that the Beijing-Zhangjiakou high-speed railway is equipped with the Chinese Train Control System Level 3 (CTCS-3), along with three Radio Block Centers (RBCs) and multiple Automatic Train Protection (ATP) systems provided by Hollysys, enabling precise and safe operation.

RBC and ATP are core safety equipment of high-speed rail train control system, which continuously communicate with onboard and offboard equipment, enabling real-time information exchange between train and ground. They function like a "central nervous system" for safe and coordinated train operation.

Ensuring both punctuality and safety

"Behind the punctuality of high-speed rail is truly the train control system," He Chunming, vice president of Hollysys Group, told CGTN.

The system consists of both onboard and ground-based equipment, responsible for managing train spacing and speed. As train speeds increase, manual control by drivers becomes increasingly difficult.

"Braking distance is directly related to speed," said He. "When a high-speed train is running at 350 km/h, the braking distance needs to be about 20 kilometers."

To ensure safety, the system must continuously calculate safe operating speeds based on information far ahead of the train.

"To determine a safe speed, we need to obtain all data within about 20 kilometers ahead. Now, data from up to 32 kilometers ahead is already available." said He. "Only with this level of information can the system calculate safe speed for each segment."

Speed control is not only about distance. Conditions such as gradients, curves, and switches will all have an impact.

"For example, an uphill or downhill slope will have significantly different effects on deceleration," said He, "and if a train enters a curve or switch at excessive speed, it could derail.

"Therefore, all information within 20 or 30 kilometers ahead must be integrated to generate a unified safe speed."

High-speed rail systems are built on very strict safety principles. He noted that if communication is interrupted, the train must stop. "Because once we cannot confirm whether the information is up to date or accurate, we must follow the fail-safe principle."

In railway signaling design, any fault must lead to a safe outcome – the fail-safe principle. If communication is lost beyond certain duration, the system discards all data and triggers an emergency brake.

Although highly automated, high-speed rail does not eliminate human oversight.

"The automated driving system reduces the driver's workload, and about 90% of operations can be automated, but some key points still require human confirmation," said He.

Developing such systems is a long process. A railway control system takes 5 to 8 years from development to deployment.

More comfort through intelligent speed control

Human driving can be inconsistent, and frequent acceleration and braking reduce comfort and efficiency.

Intelligent systems incorporate experienced drivers' strategies into their control algorithms, automatically generating optimal speed curves that balance punctuality, comfort and energy efficiency, enabling the train to run more smoothly and efficiently.

In the future, travel could be more seamless with the advancement of "four-network integration," referring to the deep integration of mainline railways, intercity railways, suburban railways and urban rail transit systems. In this framework, rail services would function as a unified mobility network rather than separate systems.

He noted that this technology is still under development. As a global provider of rail transit control systems and services, Hollysys Group has deployed train control systems on more than 80 main railway lines across China, covering over 16,000 kilometers in total. It is leveraging its accumulated technological strengths to turn this vision into reality.