How are automatic signals controlled?

Related questions

1. What does run signal do?
2. What is moving block system?
3. Do trains turn around?
4. What is fixed block Signalling?
5. Do trains have red lights?
6. When approaching a railroad crossing with flashing lights you must?
7. How do automatic train signals work?
8. What is Recfm?
9. Why do trains have signals?
10. What activates a train signal?

Tags

1. #signals
2. #between
3. #railways
4. #movement
5. #designed
6. #increased
7. #collision
8. #other
9. #allow
10. #trains
11. #their
12. #manner
13. #controls
14. #capacity
15. #system
16. #operation
17. #reduced
18. #using
19. #follow
20. #blocks
21. #without
22. #costs
23. #introduction
24. #operating
25. #automatic
26. #direction