Signalling

Question 1

Why have signals?

Answer 1

Safe method to control trains

Route indication

Question 2

Signals protect a section of line called the block section. How can the block section be controlled?

Answer 2

Track Circuit Block. Detecting trains occupy track circuits.
Axle counters. Track equipment records the number of axles into and out of section
Absolute block. Signallers will allow 1 train to enter the block section at any one time using block instruments

Question 3

What are the signals throughthe Absolute block section?

Answer 3

From Section signal through Distant signal to Home signal

Question 4

Track Circuit block operation definition?

Answer 4

Low voltage is passed through the rails of a section of track.
The metal wheels of the train will short the circuit.
System is wired to fail safe so if broken rail etc the track circuit will show as occupied.

Question 5

Types of signal identification plates?

Answer 5

Controlled signal 
Automatic signal 
Semi automatic signal 
Intermediate block signal 
Distant signal 
Outer distant signal 
Banner repeating signal 
Co Acting signal

Question 6

Controlled signal definition?

Answer 6

A signal operated by the signaller, some of which may be set by the signaller to work automatically.

Question 7

Semi automatic definition?

Answer 7

A signal operated by the passage of trains.
Controlled by the signal box.
Ground frame

Question 8

Automatic signal definition?

Answer 8

A signal operated by the passage of trains.

The signaller can place some automatic signals to danger.

Question 9

Distant signal definition?

Answer 9

Cannot show a stop aspect or indication.
Yellow arm with fishtail.
Black Chevron.
Yellow and green lights
If arm horizontal trains can proceed but should prepare to stop at the next signal. Yellow light at night.
If arm raised or lowered by 45° it means all associated signals to the distant signal will show a proceed aspect. Green light at night.
Distant signals identified by a white triangle of letter R.
Outer distant signals identified by RR.

Question 10

Intermediate block home signal definition?

Answer 10

A stop signal that controls the exit from an intermediate block section, and the entrance to an absolute block section or another intermediate block section.

Question 11

3 aspect signalling sequence?

Answer 11

Green aspect - next signal displaying proceed aspect.
Yellow aspect- caution, be prepared to stop ag next signal.
Red aspect- danger. Stop.

Question 12

4 aspect signalling- normal sequence?

Answer 12

Green aspect - next signal displaying proceed aspect.
Double yellow aspects - preliminary caution, be prepared to find the next signal displaying a single yellow aspect.
Yellow aspect- caution, be prepared to stop ag next signal.
Red aspect- danger. Stop.

Question 13

Junction indicator definition?

Answer 13

A junction indicator is normally located above the signal and will display a line of 5 white lights when a proceed aspect is displayed.
Straight route will have no JI.
Top to bottom on LHS 1 to 3
Top to bottom on RHS 4 to 6.

Question 14

Route indicator definition?

Answer 14

The indicator will display a letter or number to show the route onto which the movement is being signalled.
Provided at the signal.
Route indicator may also be associated with a JI.

Question 15

Flashing yellow aspects definition?

Answer 15

Facing points at a junction ahead are set for diverging route with lower speed than straight route.
4 aspect flashing signal is
Green - 2 flashing yellows - 1 flashing yellow - 1 steady yellow - red
3 aspect flashing signal is
Green - 1 flashing yellow- 1 steady yellow- red.
Ji is normally on steady yellow signal.

Question 16

Position light signals definition?

Answer 16

Position light signals are normally positioned at ground level independent of a main aspect.
When travelling on authority of main aspects, position light will show proceed.
The position light identification plate may have a direction arrow to show the line to which the signal applies.
One red light means Stop.
2 horizontal red lights means Stop
2 white diagonal lights authorises driver to proceed at caution towards the next train, signal, or buffer stop. Be prepared to stop short of any obstruction.

Question 17

Position light signals that display a yellow aspect definition?

Answer 17

1 yellow or 2 horizontal yellow lights means that the signal can be passed in the stop position when the movement is being made towards the shunt neck or siding but not the running line. The route may be obstructed by a train or vehicle.
If position light is showing 2 white diagonal lights it authorises the driver to proceed at caution towards the next train, signal or buffer stop. Be prepared to stop short of any obstruction.

Question 18

Position light associated with a main aspect definition?

Answer 18

Normally positioned below the main aspect.
Normal position light signal is unlit, must obey main aspect.
When the associated position light shows 2 white diagonal lights (main aspect is red) it authorises the driver to proceed at caution towards the next train, signal or buffer stop. Be prepared to stop short of any obstruction.

Question 19

Semaphore signals- Distant signal definition?

Answer 19

Yellow fishtail with black Chevron.
Yellow and green lights.
Caution - arm horizontal, at night shows yellow light. Be prepared to stop at the next signal or other specific place.
Clear - arm raised of lowered by 45°, at night shows green light. All associated stop signals will be clear.

Question 20

Semaphore signals - Stop signal definition?

Answer 20

Red arm with white vertical stripe.
Red and green lights.
Danger - arm horizontal. Red light at night.
Clear - arm raised or lowered by 45°. Green light.

If stop and distant signal combined. Stop is a section signal. Distant worked from signal box ahead.

Question 21

Semaphore signals - route indications

Answer 21

Stepping
Stacking
A route indicator
Read Top to bottom and Left to right

Question 22

Semaphore signals - subsidiary signal definition?

Answer 22

Are associated with main semaphore stop signal.
Subsidiary signal will be below main semaphore signal.
Subsidiary signal is white horizontal arm with red frame. Has red and green lights.
When subsidiary signal is horizontal is normal and you must obey main semaphore signal.
When subsidiary signal is raised by 45° it authorises the driver to pass the main signal at danger.
Proceed at caution towards the next train, signal or buffer stop. Be prepared to stop short of any obstruction. At some locations C or S may also show for calling on or shunting purposes only.

Question 23

Semaphore shunting signal, red aspect definition?

Answer 23

White disc with red bar. Red and green lights.
Danger - red bar horizontal. Red light. Stop.
Proceed - raised or lowered by 45°. Green light. Proceed at caution as far as the line is clear.

Question 24

Semaphore shunting signal with yellow aspect definition?

Answer 24

White or black dice with yellow arm. Yellow and green lights.
Stop - arm horizontal. Yellow light. The driver may pass the stop signal in the stop position when the movement is towards the shunt neck or siding and not the running line.
Proceed - arm raised or lowered by 45°. Green light. Proceed at caution as far as the line is clear.

Question 25

Signals not in use?

Answer 25

White or black cross.

Question 26

Limit of shunt signal or indicator?

Answer 26

2 horizontal red lights.
Shunt limit board rectangle board.
Limit of shunt circle board
If passed SPAD.

Question 27

Stop boards?

Answer 27

Red circle, with word STOP and other instructions.

If passed is a SPAD.

Question 28

Possession limit board?

Answer 28

PLB identifies the boundary of possession.
Board is red and double sided.
Steady or flashing red light.
If passed SPAD.

Question 29

Work site marker boards?

Answer 29

May be provided within a possession of a running line.
Board is yellow. Double sided.
2 flashing red lights indicate entrance.
2 flashing yellow lights indicate exit.
Authority from engineering supervisor is needed to pass.
Both indications treated as a stop signal.

Question 30

SPAD indicator

Answer 30

Blue frame.
3 red lights
Top and bottom flash.
Middle steady with word stop.
If illuminated musg stop and call signaller.