Signalling General Flashcards
What are the two types of train movements?
Running Move and Shunting Move
What speed are shunting moves?
Typically low speed at <40kph
What are Home signals?
Control entry of trains into the station
What are distant signals?
Warning signals and placed braking distance from the home signals.
If driver has good visibility of home signal, what can be used alternatively to a distant signal?
Beacons
What are Starter signals?
Signals that allow the departure of a train from the station.
What aspects does a Distant signal normally have?
Caution (Yellow) and Proceed (Green)
What speed does a flashing yellow indicate a driver should travel at?
40kph
What are the three important requirements from points before a signal can be cleared over them?
Set, Locked and Detected
What is the lowest a track circuit drop shunt should be?
0.5 ohms
What track circuit should be used for a track with very low usage?
Impulse Track Circuit
Maximum track circuit length for jointless track circuits?
600-700m
What is the warning time provided to pedestrians at Level Crossings?
28 seconds
What does ELD stand for?
Earth Leakage Detector
What does HRC stand for?
High Rupturing Capacity (fuse type we use)
What does MEN stand for?
Multiple Earthed Neutral
What does MOV stand for?
Metal Oxide Varistor
What does RCD stand for?
Residual current device?
What is the device called with RCD and CB in one?
RCBO
What does SRF stand for?
Surge Reduction Filter
Where is Super Control used?
When a signal is within 60 metres of a level crossing. Super Control operates a signal even when the signal is at STOP.
What is an FR and what is it used for?
FR is a Traffic Relay and is used to show no opposin routes have been called, the opposing block direction has not been given and there is no traffic coming in the reverse direction.
What is a BR and what is it used for?
BR is a Block Control Relay. When energised, it proves no opposing routes have been given (as opposed to given, as in the FR).
What is an FSR and what is it used for?
Traffic Stick Relay indicates a train is on the block.
What is ALSR and what is it used for?
Approach Locking Stick Relay. ALSR drops when activated and is used to prevent any opposing signals from being called. ALSR also locks point sin the route.
What are the stages of clearing a signal?
Expand on this later
What is a GSR and what is it used for?
GSR is the Signal Stick Relay. It proves a train has gone past the signal, which was clear. i.e. it proves the signal was used after clearing. The relay picks up when the train uses the signal.
What is a JUSR and what is it used for?
JUSR is a Timed Route Stick Relay. Checks the tracks to the next signal are clear. Drops when activated.
This relay checks the route points and tracks. It also back proves the signal to which it refers (i.e. ALSR and RPR deactivated).
What does RPR stand for?
Route Proving Relay
What does RPR do?
It shows no opposing signals have been called or given.
What does TDU stand for?
Time Delay Unit
What does a TDU do?
Provide a 4 second delay on the first track repeat relay used in an interlockig
What does TJR stand for?
Track Timing Relay
What does a TJR do?
Starts timing when the track is occupied. The relay is used to indicate a track has been occupied for a certain length of time and thus used to approach clear signals or release locking of signals and points.
What does a TFJR do?
TFJR allows a signal to approach clear up to a flashing yellow aspect.
What does a TAJR do?
TAJR allows a signal to approach clear up to an aspect other than a flashing yellow
What does ALSR stand for?
Approach Locking Stick Relay
What does an ALSR do?
It is used to prevent any opposing signals from being given and locks points in the route.
What is the normal state of the HR/DR?
Down
What is the normal state of the ALSR?
Up
What does GSR stand for?
Signal Stick Relay
What is the GSR used for?
Proves that a train has used a signal.
What is the normal state of the GSR?
The GSR is normally down
What happens to the GSR when a train uses the signal?
It Picks
What does JUSR stand for?
Timed Route Stick Relay
What is the JUSR used for?
It checks that the tracks to the next signal are clear. It checks the route points and tracks.
Does the JUSR detect the overlap?
No
When would a USR instead of JUSR be used?
The timing would be removed in the case of a leading shunt.
What does the RPR backprove?
The NPR
What is the NPR/RPR
The first repeat of the telemetry (NRR and RRR).
What does RR stand for?
Reed Relay or Registry Relay
What does WLR stand for?
Points Locking Relay
What does the WLR being up indicate?
That the points are free to move
What does the WLR being down indicate?
That the points are not free to move
What happens to the WLR when a signal using the points is called?
WLR drops meaning points are locked
What does NLR stand for?
Normal Latched Relay
What does the NLR/RLR require?
- Requires the points are free to move (WLR energised)
- Checks which calling relay (NPR/RPR) is energised
- Backproves the opposing LR
What does NKR/RKR do?
Indicates the points machine detection
What does WJR stand for?
Timed Points Protection Relay
What is the purpose of the WJR?
Prevent damage to the points machines
When does the WJR start timing?
When the detection and the lockng relays are out of correspondence for excessive time.
What does WJCR stand for?
Timed Points Contactor Relay
What does the WJCR do?
Connects power to the points machine
What state does the WJCR need to be in to provide power to the points machine?
WJCR needs to be UP
When does the WJCR drop?
When the WJR picks
What does the HR stand for?
Initial Signal Control (Clearing) Relay
What does the HR do?
- Checks the path to the next signal is clear, including the overlap
- The signal has been called (RPR Up)
- The points in route are to the correct position, locked and detected
- The points in the overlap are detected in the correct position
Does the HR detect points in the overlap?
Yes
What does the UHR stand for?
Route Initial Signal Control (Clearing) Relay
When is the UHR used instead of the HR?
When the signal is being called into a junction
Is the HR proven to be down in the UHR?
Yes
What does FHR stand for?
Flashing Initial Signal Control Relay
Why is the FHR different to the HR?
The FHR detects the points in the overlap are not in the correct lie, but all other conditions to get HR are satisfied.
Should the HR and UHR be proven down in the FHR?
Yes
Does the FHR activate approach locking?
Yes
What does the DR stand for?
Green Signal Control Relay
How is the DR different to the HR?
- Ensures the route is locked (ALSR down)
- Initial control relay (HR) is up
- The next signal is cleared
What does the HPR stand for?
Yellow Signal Control Relay
What does the HPR do?
Controls clearing the signal to yellow or green
How is the UHPR different to the HPR?
UHPR refers to a route.
UHPR can never clear the signal to green.
What does the UECR stand for?
Route Light Checking Relay
When does the UECR pick?
When the route indicator lights are proved lit by means of measuring the current drawn.
What does FHPR stand for?
Flashing Yellow Signal Control Relay
What does the FHPR do?
Controls the clearing of the signal to flashing yellow.
What does the DPR do?
The DPR is the control relay used to produce a green aspect in a two aspect signal.
What does the RGPR stand for?
Red Signal Proving Relay
What does the RGPR do?
Indicates the signal control relays have not been energised or the signal is still at red.
What does the FPR stand for?
Flashing Control Relay
What does the FPR do?
Controls the AFR and BFR to produce the on/off effect of a flashign yellow aspect.
Which of AFR and BFR controls the signal being lit?
BFR
What does the GR stand for?
Shunt Light Control Relay
What does the GR do?
Controls lighting of shunt signals
What does the NKLPR mean?
Points are in Normal, Locked and Detected
What is in the NKLPR circuit?
- Point locked (WLR down)
- Correct position (NKR up)
- Detection in correspondence with Locking Relay (NLR up)
What does the USR do?
Holds the route and will not allow another route to be set over those tracks until the train has actually cleared the tracks.
What does AS stand for?
Aerial Survey
When is a running move signal called “Approach Locked”?
Once a signal has been cleared and approach tracks are occupied
How long is the standard time for Approach Locking on a running move signal?
240 seconds or 4 minutes
Why is the Approach Locking on a running move signal 240 seconds?
To allow for the signal to be replaced whilst the driver of the train is in view of the signal and allowing the route to be maintained until the train has come to a stop or past the signal.
What does the SPECIAL column of a control table for a signal mean?
Conditions to show train has come to a halt on the berth track of an opposing signal. The time is such that the train is travelling extremely slowly or stopped.
What does the ADDITIONAL ASPECT REQUIREMENTS column of a control table for a signal mean?
The conditions for a signal to clear to a flashing yellow.
What does the asterisk or hash beside a condition or above a column indicate?
If all * or # conditions are met, the signal will clear to a yellow. If not all conditions are met, the signal will only clear to a flashing yellow.
How would “Signal Normal” be implemented in relay control logic?
ALSR energised and RPR de-energised
