Where is a repeater signal most commonly found?

A repeater signal is most commonly found in areas where visibility is limited due to changes in track alignment or obstructions. In particular, curves pose a challenge for train operators because the line of sight can be obstructed, making it difficult for them to see the next signal. A repeater signal helps by providing an indication of the status of the upcoming main signal, even when it is not directly visible.

In straight tracks, signals can be easily seen from a distance, reducing the need for a repeater. At junctions, the configuration of multiple track alignments can lead to complex signal arrangements, but the need for repeaters is generally less pronounced than in curved sections where a train's speed and line of sight can be significantly impacted. Similarly, while tunnel sections might also have visibility challenges, the design of signal placements often addresses this through different signaling strategies rather than relying primarily on repeaters.

Therefore, the positioning of repeater signals in curves is crucial for ensuring train operators have the necessary information to safely navigate through areas where signals could be obscured.