Signals - ABS

Question 1

What does ABS stand for?

Answer 1

Automatic Block Signalling

Question 2

What are the 2 variances of Automatic Block Signalling?

Answer 2

• Double Line (Designated Up and Down lines)
• Single Line (Bi-Directional running over a Single line)

Question 3

What are the 2 ways ABS signals can be controlled?

Answer 3

• Locally
• Remotely

Question 4

What is the object of the ABS system?

Answer 4

• Allows: Multiple trains proceeding in the same direction, limiting 1 per track section at a time
• Prevents: On bi-directional ABS, no more than 1 train in opposing directions at a time in the whole block section

Question 5

What is a Station Limit?

Answer 5

A portion of line that is operated under the direct control of a signaller and protected by the positioning of Home Signals

Question 6

What is the portion of line protected by Station Limits on the ABS system?

Answer 6

Between the Arriving Home Signal and the first Automatic Signal after the Departing Home Signal

Question 7

How is the object of the ABS system achieved?

Answer 7

• Electronically securing the Fixed Signal at Stop to prevent trains proceeding in the same direction
• On bi-directional lines, Electronically controlled by the track circuit and displaying stop