Signals Flashcards
What is the object of the Automatic Block Signalling (ABS) System and how is it achieved?
Where 2 or more trains are to proceed in the same direction:
Object | To prevent more than one train being in a track section at the same time
Achieved | By securing the fix signals at stop, unless the track section ahead is clear
On bi-direction lines:
Object | To prevent trains running in opposite directions in a single line section at the same time
Achieved | Signals controlled by the track circuit and display a Stop indication. Stopping a train from entering the single line section from the opposite end.
ABS operates either by track circuitry or axle counters
What are the station limits for ABS?
From the arriving home signal to the first automatic signal after the departing home signal.
Or
If there’s no departing home signal. It’s from the arriving home signal to the first automatic signal ahead.
What are the 2 types of ABS?
- Automatic Block Signalling - Double line
- Automatic Block Signalling - Single line
What is the object of the Automatic and Track Control System (ATC) and how is that achieved?
Two or More Trains in the same direction:
Object | Prevent more than one train being on a track section at the same time
Achieved | By fixed signals being controlled by track circuitry protecting the train in advance
Opposing direction movements:
Object | Prevent more than one train moving through the single line section
Achieved | By opposing departure signals controlling the entrance to the section, being secured at stop and unable to be placed at proceed while set for opposing movements
What are the Station limits for ATC?
The portion of line between opposing ATC Home Arrival signals.
3P
🟢
🔴
Clear Normal Speed
P - Points are set
T - Track is clear
S - Track Speed
N - Next signal is a proceed aspect
3P
🟡
🔴
Normal Speed Warning
P - Points are set
T - Track is clear (until next fixed signal)
S - Track Speed but be prepared to stop
N - Next signal is at Stop
3P
🟡
🟢
Reduce to Medium
P - Points are set
T - Track is clear
S - Track Speed but be prepared to reduce to 40km/h
N - Next signal is a medium aspect
3P
🔴
🟢
Clear Medium Speed
P - Points are set
T - Track is clear
S - Max 40km/h
N - Next signal is a proceed aspect
3P
🔴
🟡
Medium Speed Warning
P - Points are set
T - Track is clear
S - Max 40km/h but be prepared to stop by the next fixed signal
N - Next signal is at Stop
3P
🔴
🔴
STOP
P - Points may or may not be set
T - Track may be occupied
S - STOP. Set reverser to OFF or controller to Neutral
N - Next signal is unknown
3P
🔴
🔴
🟡
Low Speed Caution
P - Points are set
T - May or may not be set
S - Max 15km/h but be prepared to STOP
N - Next signal unknown but will most likely be at STOP
3P Dwarf
🔴
🔵
🟣
STOP
P - May or may not be set
T - May or may not be occupied
S - Stop. Set reverser to OFF or controller to Neutral
N - Next signal is unknown
**3P Dwarf **
🟡
Low Speed Caution
P - Points are set
T - May or may not be occupied
S - Max 15km/h but be prepared to stop
N - Next signal unknown but prepare to stop
3P Dwarf
🟢
Clear Low Speed
P - Points are set
T - Track is clear to the next signal
S - Speed is Max 15km
N - Next signal is a proceed aspect
What are the Banner Indicators?
🟢 = ⚪️
⚪️
⚪️
🟡 = ⚪️
⚪️
⚪️
🔴 = ⚪️⚪️⚪️
What are the Repeating Signals?
🟡
🟡
= Warning
🟢
🟡
= Proceed
What are the types and classes for 3P Signals??
Type
- Light
Class
- Home
- Automatic
- Dwarf
What do Home signals protect?
- Stations
- Signal Boxes
- Sidings
- Junctions
- Level crossings
What movements are Dwarf and Disc Signals used for? (Between)
Movements between:
- Siding to Siding
- Siding to Running line
- Running like to Running line
- Running line to Siding
What are the 3 main types of Route Indicators?
Arrow Type
- Painted arrows
- Illuminated arrows
Letter Type
- Dual gauge route indicators
- Illuminated letters
- Theatre type
Feather Type
How is a Home Signal with an ‘Illuminated A’ treated?
It is treated as an Automatic Signal as this indicates the signaller has switched out.
What are the two types of 2P Signals?
- Disc
- Light
What are the classes of 2P Signals?
- Home
- Dwarf
- Disc
- Calling On
- Distant
2P Home
🟢
Proceed
P - Points are set
T - Track is clear until next fixed signal
S - Track speed but be prepared to STOP
N - Next Signal is unknown
2P Home
🔴
STOP
P - Points may or may not be set
T - Track may or may not be occupied
S - STOP. Set controller to Neutral or reverser to OFF
N - Next Signal is Unknown
Disc
🟢
Proceed
P - Points are set
T - Track may or may not be occupied
S - Speed is Cautiously but be prepared to stop
N - Next Signal is unknown
Disc
🔴
STOP
P - Points may or may not be set
T - Track may or may not be occupied
S - STOP. Set controller to Neutral or reverser to OFF
N - Next Signal is Unknown
2P Dwarf
🔴
🔵
🟣
STOP
P - May or may not be set
T - May or may not be occupied
S - Stop. Set reverser to OFF or controller to Neutral
N - Next signal is unknown
2P Dwarf
🟢
Proceed
P - Points are set
T - May or may not be occupied
S - Speed is Cautiously but be prepared to stop
N - Next signal is unknown
2P Siding Dwarf
🔴
🟡
Siding
Proceed
P - Points are set
T - May or may not be occupied
S - Speed is Cautiously but be prepared to stop
N - Next signal is unknown
2P Siding Dwarf
🔴
⚪️ (Extinguished)
Siding
Normal
P - May or may not be set
T - May or may not be occupied
S - Stop. Set reverser to OFF or controller to Neutral
N - Next signal is unknown
What are the exceptions for passing a Home Signal?
- Defective
- Single-line Working
- Track circuited/Obstructed with no low speed caution
What are the exceptions for passing a Dwarf or Disc Signal?
- Defective
- Single-line working
What are the exceptions for passing an Automatic Signal?
- Rule 1 - Section 3
- Assisting a disabled train
What Home Signals are controlled in the MURL?
- Junctions
- Entry/Exit of loop
- End of PLT’s
What are the exceptions for passing a Home Departure Signal on the ATC network?
- Defective
- Assisting a disabled train
What are the exceptions for passing a Home Arrival Signal on the ATC network?
- Defective
Whats the Authority to pass a Defective Home Signal protecting points?
Signallers Caution Order
Whats the Authority to pass a Defective Home Signal not protecting points?
Verbal permission by Signaller
Whats the Authority to pass a Home Signal during Single-line Working?
Pilot’s Authority
Whats the Authority to pass a Home Signal when it is Track circuited/Obstructed with no low speed caution?
Verbal permission or green hand signal by Signaller and a competent worker to pilot the train.
