Research and implementation of low-frequency information extension technology for ZPW-2000 track circuit
TL;DR
A low‑frequency code expansion technology compatible with the existing system is proposed, which provides critical support for fine‑grained train control in special terrains, reduction of train tracking intervals on existing high‑speed lines, and antiinterference performance in complex electromagnetic environments for overseas railways.
Abstract
The ZPW-2000 track circuit is a core signaling equipment in Chinese railways. Its low‑frequency coding capability directly determines the information transmission capacity and operational safety of train control systems. The existing system supports only 18 low‑frequency codes, which cannot meet the requirements of higher speeds and more complex railway lines. To address this limitation, this paper proposes a low‑frequency code expansion technology compatible with the existing system. Four new low‑frequency codes (8.1 Hz, 9.2 Hz, 30.1 Hz, and 31.2 Hz) are added to the original 18 codes. By modifying only the software of the existing transmitter hardware, the extended low‑frequency frequency‑shift signals can be generated while maintaining the “2‑out‑of‑2” safety architecture. Experimental tests using a CD96‑ 3Z instrument show that the frequency deviation of the new codes under all carrier frequencies is within 0.01Hz, meeting the standard requirement of ±0.03Hz. This technology provides critical support for fine‑grained train control in special terrains (e.g., the Sichuan‑Tibet Railway), reduction of train tracking intervals on existing high‑speed lines, and antiinterference performance in complex electromagnetic environments for overseas railways.
