Complex sentence: His design consisted of electrically operated discs located atop small trackside signal huts, and was based on an open track circuit, meaning that when no train was within the block no power was applied to the signal, indicating a clear track.
Split into simpler sentences: His design consisted of electrically operated discs located atop small trackside signal huts, and was based on an open track circuit. When no train was within the block no power was applied to the signal, indicating a clear track.