Bijsignalering

Bijsignalering is a term used in Dutch railway signaling to describe auxiliary signals placed beside or near main route signals to convey supplementary information to train drivers. The primary purpose is to improve safety and operational clarity by providing information that cannot be conveyed by the main signal alone, or to give redundancy in the signaling system.

What and where: Bijsignalen are typically located at junctions, level crossings, near stations, or in yards, and are coordinated with the interlocking that controls the main signals. They may indicate aspects such as a permitted speed for the upcoming track, the status of a turnout, or that a route has been released, complementing the main indication. The exact meaning of a bijsignaal depends on national signaling rules and the specific interlocking installation; the signaling code is documented in rulebooks used by train crews.

Operation and control: In older installations, bijsignalen could be mechanical or lamp-based; modern networks use electronic signaling where bijsignals are generated by the same computer-based interlocking as the main signals. They are designed to be fail-safe and are integrated with procedures for maintenance and fault management.

Relation to safety and regulation: Bijsignalering falls under national railway signaling standards and driver training. Proper interpretation by the train crew is essential for safe operation, and operators regularly review bijsignalering in risk assessments and during line modernization efforts.

History and usage: The concept arose from the need to provide additional cues in complex track layouts or under limited visibility. While most common in Dutch railways, analogous systems exist in other countries under different terminology.