Late at night on December 23, 2021, Gao Chunhai, chairman of Traffic Control Technology Co., LTD. (referred to as "TCT"), and his party came to the site of Beijing Metro Line 11 - Winter Olympic Branch Line to check the progress of the project. At the scene, the fifth-generation complete signal system, namely the train control system based on vehicle-vehicle communication (referred to as "vehicle-vehicle communication") and the train autonomous sensing operation system (referred to as "Hawk-eye system"), was witnessed.