A track circuit is an electrical circuit installed on a railway track that detects trains and controls signals and points. Some synonyms for track circuits include train detection systems, signaling circuits, and interlocking circuits. Train detection systems are designed to identify the presence of trains on a track and ensure that signals are set accordingly. Signaling circuits, on the other hand, refer to the electrical circuits that control signals and are incorporated in track circuits. Interlocking circuits are used as a safety feature to prevent conflicting train movements, and they rely heavily on track circuits to signal train occupancy and regulate trains' speeds.