How many types of signals are there in railway?

Related questions

1. What is calling on signal?
2. What do train signal lights mean?
3. What is a controlled signal?
4. What is moving block system?
5. What is fixed block Signalling?
6. How do train crossing signals work?
7. How does Indian Railway Signal work?
8. How does Indian railway work?
9. What is a subsidiary signal?
10. What is signal overlap?

Tags

1. #light
2. #color
3. #driver
4. #given
5. #aspects
6. #meaning
7. #verbal
8. #different
9. #macls
10. #types
11. #particular
12. #convey
13. #signal
14. #signals
15. #indications
16. #medium
17. #aspect
18. #determined
19. #means
20. #multiple