3 POSITION SIGNALS Flashcards
What information does a driver get with 3 position signaling?
Points - set or not
Track section ahead, - clear or occupied
Speed - normal/ medium
Next signal - stop or proceed
What does a greenlight inform the driver about the next signal ahead?
Next signal will be a another proceed aspect
What does a yellow light inform the driver about the next signal ahead?
Next signal will be at stop
What does a medium Speed aspect tell us
Medium Speed aspects are used where:
- there are junctions or diverging running lines
- Speed of the train is to be reduced to medium due to short track sections
What type of signal are three position signals
LIGHT type
What is A light
B light and
C light?
A - top
B - bottom
C - on Home Signals
What are the classes of signals three position?
Home
automatic
dwarf
What do you three position home Signals protect ?
Stations
signal boxes,
sidings
level crossings
junctions
Why is a tramway square protected by Home signals?
Because the power in the overhead has to be switched over to accommodate the different voltagei used by different vehicles
(Tram 600 v
Train 1500 v)
What is the purpose of automatic signals?
Automatic signals purpose is to expedite the passage of trains by dividing a long section of track into shorter sections
What is the purpose of a home signal and how are they controlled
Home protect sections of track, and are regulated by signallers/ area controllers to Regulate trains and protect conflicting movements
Who controls dwarf signals?
Signalers
What do dwarf signals control train movements from?
Running line to running line
running line to siding
siding to running line
siding to siding
Which signals are absolute
Home, dwarf, and disc
(Meaning they require permission from signaller to pass when at stop)
Which signals are permissive
Automatic
Drivers can self authorize to pass the signal at stop R1S3
What colors do home and automatic signals display?
🔴 red
🟡 yellow
🟢 green
What colors do dwarf signals display?
🔴
🟣
🔵
🟢
🟡
Can an automatic signal display a low speed caution?
No
What is a marker light?
It’s just a smaller light that Only ever displays the color red.
Aspect and meaning?
🟢
🔴
CLEAR NORMAL SPEED
- Points set
- Track clear
- Track speed
- Next signal at proceed
Aspect and meaning?
🟡
🔴
NORMAL SPEED WARNING
- Points set
- Track clear
- Normal track speed,
- Next signal at stop
Aspect and meaning
🟡
🟢
REDUCE TO MEDIUM
- Points set
- Track clear
- Normal track speed
(must reduce to 40 before next signal) - Next signal proceed
- If next signal observed is an improved aspect, requirement to reduce speed, no longer applies
Aspect and meaning
🔴
🟢
CLEAR MEDIUM SPEED
- Points set
- Clear track
- 40 for whole section up to next signal
- ATC: 40 only until whole train has cleared
the points (home Dep. sig.) - Next signal at proceed
Aspect and meaning
🔴
🟡
MEDIUM SPEED WARNING
- Points set
- Track clear
- 40 up to the next signal
- Next signal at stop