| # | Concept | Culture | Statement | Freq. |
|---|---|---|---|---|
| 1 | railway signal | United States | In the United States, railway signals are essential for safe train operations, utilizing color-coded lights and symbols to guide train movements. | 6 |
| 2 | railway signal | South Asian countries | Railway signals are essential for controlling train traffic in South Asian countries, but may be subject to greater challenges and less standardization in maintenance and implementation. | 1 |