Untersignale

Untersignale is a German term meaning sub-signals or subordinate signals. In technical contexts it designates indicators that operate under the authority of a primary signal, providing additional information relevant to a system’s state or to the next action required by an operator or automatic control. The formulation and use of Unter Signale can vary by field and by national practice, but the basic idea is that they supplement a main signal rather than replace it.

In railway signaling, the term appears in historical and descriptive literature as a generic label for signals that accompany or follow Hauptsignale (main signals) to convey auxiliary information about routing, speed, or conditions of movement. The exact form, meaning, and naming of Unter Signale differ among rail administrations, and in some systems similar functions are described using terms such as Nebensignale (subsidiary signals) or Vorsignale (pre-signals). Today, many networks rely on different terminology or standardized interlocking concepts, and the use of Unter Signale as a distinct category is less common in modern practice.

Beyond railways, Unter Signale can also refer to status indicators for subsystems within a larger control or monitoring setup. In industrial automation or computer-controlled processes, subordinate signals help coordinate subcomponents without requiring operators to interpret the entire system at once.

Etymology: from unter- meaning “below” or “sub-” and Signale meaning “signals.”