For modern railway transportation, dynamic moving block train control systems have been well studied to shorten train tracking intervals and increase capacity. In this article, a novel train tracking method based on train-to-train communication is developed for a dynamic moving block train control system to prevent chain collisions when lead trains experience a sudden speed loss. First, a 3D dynamic safe braking model is built to show the train control mode. Second, a multitrain information synchronization method is proposed to ensure the validity of received messages. Finally, a cooperative collision avoidance mechanism is put forward. Simulation experiments are carried out with practical line data, and the effectiveness of the method is verified by a comparative simulation study with two other benchmark case studies. The results show that the proposed approach can successfully prevent chain collisions in a three-train scenario. By ensuring the normal operation of train-to-train communication through high-frequency information exchanges, the described method is able to successfully prevent chain collisions caused by abrupt decelerations on a high-density network.