ABS

Question 1

What is ABS?

Answer 1

Automatic Block Signalling

Question 2

What is another term for Automatic Signals

And

Controlled Signals?

Answer 2

Automatic or Permissive

Controlled or Absolute

Question 3

What is the object of the ABS System?

Answer 3

Trains in same direction- one train per Track Section

On Single Line - one train per Single Line Section.

Question 4

How is the Object achieved?

Answer 4

Trains in same direction - turning fixed signals to Stop unless the Track Section ahead is clear.

On Single Track Lines where trains are going in opposite directions- the signals are put at Stop by the Track Circuit preventing a train from entering Single Line Section from other end.

Question 5

What are the two mechanisms the Signalling System operates by?

Answer 5

Track Circuitry

Axle Counters

Question 6

What does the term ‘Sleeved’ mean?

Answer 6

When signaller puts signals at stop to control/stop movement on a line

Question 7

What is Station Limit on ABS?

Answer 7

From AH Signal to first Auto after DH Signal

Where there is no DH signal it is the first Auto Signal after the AH Signal