PZB

Punktförmige Zugbeeinflussung, abbreviated as PZB, is a railway safety system used primarily on German-speaking networks to enforce compliance with signal aspects and speed restrictions. It functions as a form of train protection that complements interlocking and signaling by providing an additional layer of safety in the cab. PZB is employed on many mainline routes and on networks in several neighboring countries, where it may operate alongside other protection systems.

The system consists of two main elements: a trackside interface that transmits movement authority and speed information to the train, and an on-board train protection unit known as the Zugbeeinflussungseinrichtung (ZBE). As a train approaches trackside signals or encounters speed restrictions, the trackside interface communicates the required restrictions to the ZBE. The ZBE continually monitors the train’s adherence to these restrictions and can intervene by applying braking or blocking control if the driver fails to comply, such as passing a signal at danger or exceeding permissible speed. The driver may be required to acknowledge restrictions or perform actions to restore normal operation after an intervention.

History and use: PZB was developed in the mid-20th century to provide a robust, fail-safe override independent of human reaction time and to improve safety on busy networks. Over time, it has been upgraded and maintained in many lines, and in some areas it operates in conjunction with other systems such as LZB (Linienzugbeeinflussung) or ETCS (European Train Control System) in multi-system environments.

See also: train protection systems, interlocking, LZB, ETCS.