Lichtsignals

Lichtsignals are fixed railway signals that use colored electric lights to convey permission and restrictions to train crews. They were developed to replace earlier mechanical semaphore signals and are widely used in many rail networks to control train movements, protect junctions, and support interlocking systems.

A typical signaling concept uses a limited set of colors, most commonly red, yellow, and green. Red generally means stop, green means proceed, and yellow indicates caution or that the next signal may require stopping. Some national systems add extra indications or sequences to convey further restrictions, speed limits, or diverging routes. The exact meaning of aspects and the allowed speed through a signal are defined by local signaling rules and interlocking logic.

Signals operate as part of an interlocking system that ensures safe train movements by preventing conflicting routes. They are connected to track circuits or axle counters that detect train presence and to switching equipment that controls track directions. In older installations, fixed-block interlockings were common; modern networks increasingly use computer-based interlocking and often integrate with cab signaling or train control systems such as ETCS.

Regional differences exist in the implementation and terminology. In German-speaking regions, Lichtsignale include Hauptsignale (main signals) and Vorsignale (distant signals) with standardized meanings, while other countries adapt the color logic to their own rules. Nevertheless, the general concept of color-coded lights as a safety and control tool for rail traffic is widely shared across Europe and beyond.

Recent trends focus on LED technology for greater efficiency, longer life, and lower maintenance, along with deeper integration into unified traffic management and train control systems.