noun
main signal; traffic signal
Refers to the primary signal in a system, such as a traffic light at an intersection or a main signal in railway signaling.
この交差点の主信号は、朝のラッシュ時に長く青になります。
The main traffic signal at this intersection stays green longer during the morning rush hour.
鉄道の主信号が故障すると、運行に大きな遅れが出ます。
When the main railway signal fails, it causes significant delays in operations.