Across
- 3. signal device (4 letters: HORN)
- 5. for reduced speed visibility (6 letters: SPEED)
- 8. used for day and night signals (9 letters: SEMAPHORE)
Down
- 1. to protect the train's rear (5 letters: LAMP)
- 2. Clues
- 4. of signal using color, form, and position (7 letters: VISIBLE)
- 6. of signal expressed by sounds (5 letters: SOUND)
- 7. displayed in low visibility conditions (6 letters: NIGHT)