Signals COPY Flashcards
What are the 6 classes of 2 position signals?
- Home
- Dwarf
- Disc
- Distant
- Siding Dwarf
- Calling on
What are the 2 main purposes of signal systems?
- Communicate to the driver the state of the line ahead
- Give the driver authority to proceed
What are the two types of two position signals?
- Light Type
- Disc Type
What signal is both a class and a type?
Disc Signal
What do two position Home signals protect (and positioned at)?
Stations
Signal Boxes
Sidings
Level Crossings
Junctions
What two aspects can the two position Home system show?
Red - Stop
Green - Proceed
When a two position home signal is showing proceed, are the points set and the line clear ahead?
Yes the points and line are clear.
What does a proceed aspect on a two position home signal not show?
Does not indicate if next signal is at proceed.
Driver should be prepared to stop at next signal and assume it’s at stop.
What 2 aspects do distant signals display?
- Caution
- Proceed
Why would a distant signal be at caution?
- A train is in the section
- An obstruction on the line
- A signal in the block is at danger
When coming across a distant signal at caution, can it tell you which signal is at stop?
No, it only indicates that a signal in the block is at stop
What does a call on signal mean?
A train can enter into an occupied section, past the stop aspect.
How would a driver pass a calling on signal showing proceed?
Advance cautiously past the signal and be able to stop short of any obstruction
If the home signal is clear (green) AND bottom light is on, can you proceed?
No, it would be treated as an irregular signal aspect. Treat as both signals are at their safest aspect.
What are disc signals used to control? (train movements)
- Running line to running line
- Running line to siding
- Siding to siding
- Siding to running line
What 2 aspects do disc signals display?
Stop and Proceed
What does a disc signal tell us? (PTSN)
P - Points are set
T - Track ahead may be occupied
S - Speed is reduced speed cautiously
N - Next signal is unknown so be prepared to stop
When a disc signal is at proceed, what must you be aware of?
The line may be occupied or obstructed
What is the max speed at a siding?
15km/h
What is the max speed at points? (running line to running line)
40km/h
How can a disc signal show an aspect at night?
It has a red or green light depending on if it reads stop or proceed
How do you read a set of 4 disc signals on one post?
Top to bottom, left to right
1-3
2-4
What does a two position dwarf signal control?
- Running line to running line
- Running line to siding
- Siding to siding
- Siding to running line
What are the two different types of two position dwarf signals?
Standard 2 position dwarf signal
And a siding Dwarf (fitted on same past as home signal)
What aspects can a dwarf signal display?
Stop - Red/Blue/Purple
Proceed - Green or Yellow (for a siding dwarf)
How can a siding dwarf and a call on signal be distinguished?
Call on is just the light
Siding dwarf has the light AND a siding sign
If a two position dwarf signal is at proceed, is the line clear?
No, the track ahead may be occupied
What happens when a track circuit is broken?
The signal reverts to it’s fail safe aspect (stop)
What are 3 things that can break a tracks circuit?
- Damaged track
- Obstructed track
- Occupied by another train
How does an axle counter work?
It counts how many axles enter a block and makes sure it matches with how many axles leave the block. It feeds this information to the signals to show the block is occupied or clear.
What light colours can be shown by a 3 position signals?
Red - stop/reference light
Yellow - warning
Green - clear
What information can a 3 position signals provide?
Points - set or not set
Track section ahead - clear or occupied
Speed - normal/medium track speed
Next Signal - whether next signal aspect is proceed or stop
What is the top light (A light) referring to in a 3 position signal set?
The A light refers to normal speed
What is the bottom light (B light) referring to in a 3 position signal set?
Medium speed aspect
What signal class can have a C Light or Low speed aspect?
Home signal
How can you tell a home signal and an automatic signal apart?
Home has two lights vertically
Automatic has the two lights staggered
What are the three classes of 3 position signals?
Home
Automatic
Dwarf
Why is it important to know the difference between the classes of signals?
Rules and instructions vary depending on class and location of signal
Where are 3 position signals fixed at and protecting?
Stations
Signal boxes
Sidings
Level crossings
Junctions
Which classes of 3 position signal is usually controlled?
Home signals and Dwarf signals
If you need to pass a home signal that is uncontrolled, who would you contact for permission?
Signaller/Area Controller (Signal Control Panel)
What is the primary purpose of automatic signals?
Expedite the passage of trains by dividing long sections of track into shorter sections.
Can automatic signals at stop be passed?
Yes, only if you follow Rule 1, Section 3
Which signals are classified as absolute or permissive?
Absolute - Home, Dwarf, Disc
Permissive - Automatic
How many aspects can a 3 position signal show?
6 with A & B lights
7 with A, B & C lights (only on home)
What aspect is this signal showing?
Clear Normal Speed
For a Clear Normal Speed aspect, what does the signal tell us? (PTSN)
P - Points are set
T - Track is clear
S - Speed is track speed
N - Next signal will show proceed
What aspect is shown on this signal?
Normal Speed Warning
What does a Normal Speed Warning tell us? (PTSN)
P - Points are set
T - Track is clear
S - Speed is track speed, but prepare to stop at next signal
N - Next signal will be at stop
This signal is Reduce to Medium, what speed is medium?
40km/h
What does a reduce to medium signal tell us? (PTSN)
P - Points are set
T - Track is clear (till next signal)
S - Track speed but prepare to reduce to medium by next signal
N - Next signal will be at medium aspect
What does a Red A light over a Green B light signify? (Name + PTSN)
Clear Medium Speed
P - Points are set
T - Track is clear
S - Speed is medium (40km/h)
N - Next signal will be a proceed
What is the name of this aspect and what does it tell us? (PTSN)
Medium Speed Warning
P - Points are set
T - Track is clear
S - Speed is medium (40km/h), prepare to stop before next signal
N - Next signal is at stop
What do 2 red lights on a signal mean?
Stop!
Points may not be set, track may be occupied.
When stopped at danger aspect, what should you do with your reverser?
Set to neutral or off
Marker lights to white
What is the name of this aspect and it’s PTSN?
Low Speed Caution
P - Points are set
T - Track ahead may be occupied
S - Speed is low speed 15km/h, be ready to stop short of any obstruction
N - Don’t know next signal aspect, assume next one is at safest position
What 2 locations can a low speed signal take you to?
- A siding
- Main line track/running line to running line (eg. to a station to couple with another train)
When can a Low Speed Caution never be used?
For train movements into a bi-directional portion of track
What signal aspects come before a stop aspect?
Reduce to Medium (sometimes) then Normal Speed Warning or Medium Speed Warning
What does an illuminated 65 or 80 mean on a home or automatic signal?
High speed points ahead, reduce to 65 or 80 based on what is shown.
What does an illuminated red A on a 3 position home signal mean?
Home signal has been switched to automatic as is to be treated as an automatic signal (only visible on a signal at stop)
If a signaller is operating points and signals, the signal box is referred to as?
Switched In
If the signaller is off duty, what is the signal box referred to as?
Switched out
When the signal box is switched out and running by the passage of trains, what is the mode called?
Fleeting Mode
What 3 aspects does a three position dwarf show?
Stop
Low speed caution
Clear low speed
What is the primary purpose of Banner Indicators?
They indicate the aspect of the signal ahead when a clear view of the signal cannot be obtained
Banner Indicators are not….?
They are not:
Fixed signals
Considered to be signals in advance
What signal is being repeated on the Banner Indicator when it shows 2 horizontal lines?
Stop
What aspect is shown on the Banner Indicator?
Normal Speed Warning
What signal is the Banner Indicator showing?
Reduce to medium
What aspect is the Banner Indicator showing?
Stop
Who do you report a faulty Banner Indicator to?
Train Control @ Metrol
