Automatic Block System (ABS)

Question 1

What is the object of Automatic Block Signalling?

Answer 1

To prevent trains from being in the same track section at the same time.

On bi-directional lines it prevents train crashing into each other head on.

Question 2

How is the object of the ABS system achieved?

Answer 2

by electronically securing track signals at stop, unless the track section ahead is clear, to control trains moving in the same direction.

by electronically controlling signals on bi-directional lines to display a stop indication, preventing trains from entering the same track section from opposite directions

Question 3

What are the two different types of Automatic Block Signalling?

Answer 3

• Double line
• Single line

Question 4

What is the defined Station Limits on the Automatic Block Signalling system?

Answer 4

between the arriving home signal and the first automatic signal after departing home signal.

where a home signal is not provided the first automatic signal ahead of the arriving home signal.

Question 5

What are the two ways that automatic block signalling can be controlled?

Answer 5

• locally
• remotely