As the high-speed railway network in China extends beyond 40,000 kilometers, maintaining seamless internet connectivity for passengers is becoming increasingly challenging. The demand for consistent and reliable online access is particularly crucial for travelers who spend extended hours on trains, relying on the expectation of undisturbed work, study, or entertainment. Addressing this need, a team of researchers from the School of Computer Science at Peking University has developed “HiMoDiag”—an innovative tool designed to enhance the understanding and management of network performance in extremely high-mobility scenarios.As the high-speed railway network in China extends beyond 40,000 kilometers, maintaining seamless internet connectivity for passengers is becoming increasingly challenging. The demand for consistent and reliable online access is particularly crucial for travelers who spend extended hours on trains, relying on the expectation of undisturbed work, study, or entertainment. Addressing this need, a team of researchers from the School of Computer Science at Peking University has developed “HiMoDiag”—an innovative tool designed to enhance the understanding and management of network performance in extremely high-mobility scenarios.[#item_full_content]