GENERAL NOTES
SUMMARY OF XSF FLAGS
(Communications Operation of XSF flags is required)
XSF1   Allows auto introduction of P1 in AØ after the expiry of AØ late start.
XSF2   Allows auto introduction of P2 in AØ after the expiry of AØ late start.
XSF3   Allows auto introduction of P3 in BØ after the expiry of BØ late start or in CØ, if going AØ  → CØ, after expiry of CØ late start.
XSF5   If set, inhibits P5 from introducing in CØ.
SUMMARY OF MSS FLAGS
MSS1 - Set when the CALL input is received (set until the termination conditions are met).
MSS2 - Set at the start of train phase (set until the start of intergreen of train phase).
MSS3 - Set when the FORCE input is received before TLR (Abnormal Condition 1).
MSS4 - Set when the RELEASE/ FORCE input is not reinstated before the expiry of the RELEASE  TIMER (Abnormal Condition 2)
MSS5 - Set when the RELEASE/ FORCE input is terminated without a CALL input  (Abnormal Condition 3)
MSS6 - Set when there is a break in the CABLE MONITOR input (Abnormal Condition 4).
MSS7 - Set when the BOOMS HORIZONTAL input is not received during train phase (Abnormal  Condition 5).
MSS11- Set when the CALL is deemed to be established (set until the CALL is removed).
MSS13- Set when BOOMS HORIZONTAL input is received (set until BOOMS HORIZONTAL  input is removed).
MSS14- Set when the FORCE input is received (set until the FORCE input is reinstated).
MSS15- Set when the PRE-RELEASE input is received (set until the PRE-RELEASE input is  reinstated).
GENERAL OPERATION
1.                  If in CØ, clear demands for BØ.
2.                  If going AØ → DØ or BØ → DØ, expire DØ late start.
3.                  Use BØ special all red for BØ all red if going BØ → DØ.
SIGNAL GROUP OPERATION
Signal Group 4
1.                  If going CØ → DØ, close down SG4 at the start of CØ intergreen, then re-introduce SG4 at the end of DØ late start.  
Signal Group 5
1.                  SG5 is a one-aspect (red) partially controlled right turn display.
2.                  SG5 is activated at the start of the red of the preceding phase before Track Clearance Phase (DØ).
3.                  SG5 is held red until the end of the train phase (EØ) intergreen.
Signal Group 9
1.                  SG9 is a two-aspect (red/yellow) left turn display.
2.                  SG9 is conditional on P5 demand. If there is no demand for P5, SG9 will be green (blank display).
3.                  SG9 can close down at the start of AØ, BØ & CØ intergreen when P5 is demanded provided SG9 minimum green (Special Purpose Timesetting No. 9) has expired.
4.                  SG9 uses the phase yellow when it closes down.
5.                  SG9 All Red is controlled by Special Movement Timesetting No. 1.
AØ All Red is substituted for Special Movement Timesetting No. 1.
PEDESTRIAN GROUP OPERATION
Pedestrian 1
1.                  P1 calls AØ.
2.                  P1 can introduce in AØ after the expiry of AØ late start or in E1Ø or E3Ø after the expiry of EØ late start.
3.                  P1 can overlap E3Ø → E1Ø
4.                  P1 can auto-introduce in AØ when XSF1 is set, provided AØ late start period has expired.
Pedestrian 2
1.                  P2 calls AØ.
2.                  P2 can introduce in AØ after the expiry of AØ late start or in E1Ø, E2Ø or E3Ø after the expiry of EØ late start.
3.                  P2 can overlap E1Ø ↔ E2Ø, E1Ø ↔ E3Ø, E2Ø → E3Ø.
4.                  P2 can auto-introduce in AØ when XSF2 is set, provided AØ late start period has expired.
Pedestrian 3
1.                  P3 calls CØ.
2.                  P3 can introduce in BØ after the expiry of BØ late start or in CØ after the expiry of CØ late start or in E3Ø after the expiry of EØ late start.
3.                  P3 can overlap BØ → CØ.
4.                  If XSF3 is set, P3 can auto-introduce in BØ after the expiry of BØ late start or in CØ, if going AØ → CØ, after the expiry of CØ late start.
Pedestrian 4
1.                  P4 calls CØ.
2.                  P4 calls P5 and holds SG9 red until the end of P4 clearance.
3.                  Do not introduce P4 if P5 is not running at the start of CØ or P5 is not able to introduce due to SG9 minimum green.  Introduce P4 (and P5) in next cycle (do not allow P5 to introduce in next cycle except as part of P4 transfer).
4.                  P4 can introduce in CØ after the expiry of CØ late start or in E3Ø after the expiry of EØ late start.
Pedestrian 5
1.                  P5 is a non-SCATS pedestrian.
2.                  P5 calls AØ, E2Ø and E3Ø.
3.                  P5 can introduce at the start of AØ, BØ, CØ and E3Ø.
4.                  P5 can overlap AØ → BØ, AØ → CØ, BØ → CØ, CØ → AØ.
5.                  P5 can only introduce when SG9 closes down as described above.
6.                  If XSF5 is set, P5 is inhibited from introducing in CØ.
7.                  Provide 3 seconds solid don’t walk at the end of P5 clearance before SG9 starts up.
8.                  Refer to SG9 operation.
DETECTOR OPERATION
General
1.                  Clear vehicle demands during associated phase green and yellow.
Detector 5
1.                  Detector 5 places locking calls for CØ and, when its presence timer expires, places non-locking calls for BØ and extends BØ.
2.                  Clear demands for BØ from detector 5 during SG3 and SG6 green and yellow.
Detector 18 and 19
1.                  Detectors 18 and 19 are cyclist push buttons.
2.                  The activation of detector 18 and/or detector 19 places a demand for CØ.
3.                  If CØ is demanded by detector 18 and/or detector 19, CØ minimum green is substituted by the timesetting as specified in Special Purpose Timesetting No. 16.
OPERATION OF INTERNALLY ILLUMINATED SIGNS
Relay Output 1
1.                  Relay Output 1 drives an Internally Illuminated ‘Give Way To Pedestrians’ sign during P3 walk and clearance when SG3 is green.
2.                  Relay Output 1 is activated by P8 Wait State output (PSC2003/ ATSC4) or by Special Output 1 (Eclipse) during P3 walk and clearance when SG3 is green.
3.                  Both P8 Wait State Output and Special Output 1 are set in the controller personality.
Relay Output 2
1.                  Relay Output 2 drives an Internally Illuminated ‘Give Way To Pedestrians’ sign during P4 walk and clearance when SG4 is green.
2.                  Relay Output 2 is activated by P7 Wait State output (PSC2003/ ATSC4) or by Special Output 2 (Eclipse) during P4 walk and clearance when SG4 is green.
3.                  Both P7 Wait State Output and Special Output 2 are set in the controller personality.
TRAIN OPERATIONS
1        GENERAL INTERFACING REQUIREMENTS
Electrical interfacing between the traffic signal controller and the level crossing controller is provided by a multi‑core telephone‑type cable having at least 10 pairs.  The wiring is detailed in the Standard Rail-Link Cable Termination Chart (Appendix 2).
1.1      STANDARD RAIL LINK INPUTS
For a standard installation, the following five inputs are generated by the rail crossing control system and fed into detector inputs in the traffic signal controller:
·        CABLE MONITOR  (Detector 13)  – usually ON
·        PRE‑RELEASE  (Detector 14)  – usually ON
·        RELEASE/FORCE (R/F)  (Detector 15)  – usually ON
·        CALL (Detector 16)  – usually OFF
·        BOOMS HORIZONTAL (Detector 17)  – usually OFF
Each of these inputs is generated from a rail level crossing relay.  Each can be in the on or off state.
NOTE: ‘CALL’, and ‘BOOMS’ are normally OFF state
1.2      STANDARD RAIL LINK OUTPUTS
TRAFFIC LIGHT RESPONSE (TLR)
·        This output is driven by SG10.
2        BASIC OPERATING PROCEDURE
The TYPICAL SEQUENCE CHART in Appendix 1 shows the sequence of events and the change in state of each input and output.
2.1      CALL 
On receipt of the “CALL” input (detector 16) the following will occur:
-         When the CALL presence timer expires the CALL is deemed to be established and will force the controller to go into the train operation described below.
-         When the timer expires the controller will clear all phase demands i.e. the controller will remain in the currently running phase. If a pedestrian is in WALK when the “CALL” is received then select Special purpose Timesetting No. 12 for the pedestrian walk time.
-         If the controller is changing phases when the “CALL” is received, then do not service pedestrians in the phase which is about to run.
-         A Call delay timer (Special Purpose Timesetting No. 15) is started. When this CALL DELAY timer expires, a demand is placed for Track Clearance Phase, DØ, and the controller proceeds to EØ immediately (Refer Track Clearance Phase).
-         MSS1 flag is set at the point when the “CALL” is first received. The point at which the MSS1 flag is removed is outlined in section 3.3, which relates to the provision of train compensation.
-         The controller is forced to isolated mode of operation. When on-line to the regional computer this is achieved via the MSS1 flag using VR30.
-         MSS11 flag is also set from the point when the CALL is deemed established until the CALL is removed.
2.2     TRAIN PHASE SEQUENCE
2.2.1        Track Clearance Phase
The TRACK CLEARANCE phase is DØ.
Start Timer 1 (Special Purpose Timesetting No. 17) at the start of Force (when detector 15 goes from ON to OFF).
The Track Clearance Phase (DØ) is held until Timer 1 expires or Booms Horizontal (detector 17) is received whichever comes first.
The controller then proceeds to the TRAIN PHASE, EØ.
2.2.2        Train Phase
The Train Phase is EØ
Within the Train Phase, EØ:
a.                   The Train Phase starts in E1Ø.
b.                   The train phase cycles between E1Ø, E2Ø and E3Ø, depending on demand.
c.                   The controller will rest in E1Ø if there are no other demands.
d.                   E1Ø is called by detectors 1 and 2, P1 and/ or P2.
e.                   E2Ø is called by detectors 3 & 5.
f.                     E3Ø is called by P3, P4 and/ or P5.
g.                   Special Approach 1 uses EØ Approach 1 (E1) timesetting to control SG1 extension.
h.                   Special Approach 2 uses EØ Approach 2 (E2) timesetting to control SG2 extension.
i.                     Special Approach 4 uses EØ Approach 4 (E4) timesetting to control SG6 extension.
j.                     SG1, SG2, SG6, SG8 and SG9 use EØ minimum green.
k.                   SG1 and SG2 use Special Purpose Timesetting No. 10 for their maximum extension green.
l.                     SG6, SG8 and SG9 use Special Purpose Timesetting No. 11 for their maximum extension green.
m.                 P1 can introduce in E1Ø and E3Ø and can overlap E3Ø → E1Ø.
n.                   P2 can introduce in E1Ø, E2Ø and E3Ø and can overlap E1Ø ↔ E2Ø, E1Ø ↔ E3Ø, E2Ø → E3Ø.
o.                   P3 can introduce in E3Ø and can overlap E3Ø → CØ.
p.                   P4 can introduce in E3Ø and can overlap E3Ø → CØ.
q.                   P4 calls P5 and holds SG9 red until end of P4 clearance.
2.3      TRAFFIC LIGHT RESPONSE (TLR) 
2.3.1        Description
The Traffic Light Response (TLR) Signal Group 10 is a status message that is sent from the road traffic signal controller back to the railway control equipment to indicate that the road traffic signals are ready for activation of the boom gates.
2.3.2        When the TLR is issued
The TLR is issued at the start of the TRACK CLEARANCE phase.
It is maintained until the PRE-RELEASE input is re-instated.
2.4      FORCE
The FORCE is indicated by the RELEASE/FORCE input (detector 15) going off.  This occurs when the train enters the control section causing the red lights at the crossing to flash and bells to ring.  If the FORCE is received before the TLR is sent, then the signals will be forced to flashing yellow.
On receipt of the FORCE, MSS14 is set.  MSS14 remains set until the FORCE input is removed (ie. the RELEASE/FORCE input is re-instated). MSS14 is used to monitor the CALL/FORCE interval.
2.5     BOOMS HORIZONTAL
The receipt of this input (detector 17) is an indication that all the booms have reached horizontal. On receipt of the BOOMS HORIZONTAL input, the MSS13 flag is set and remains set until the BOOMS HORIZONTAL input turns off. MSS13 is used to monitor the duration of the booms closure.
2.6      PRE‑RELEASE
2.6.1        Normal operation for one train
The re-activation of the PRE‑RELEASE input (detector 14) is an indication that the train has cleared the control section of track and that the booms are about to lift.  When it is received, the controller initiates a pre‑release sequence which directs the controller to terminate all signal groups in the train phase without violating pedestrian or minimum green times.  If a pedestrian is in walk when the PRE‑RELEASE is received, then select Special Purpose Timesetting No. 12 for the pedestrian walk time, so that normal operation may resume as soon as possible.  The controller will then proceed to the train phase All-Red interval and remain there pending reinstatement of the RELEASE/FORCE input.
On removal of the PRE-RELEASE input, MSS15 is set.  MSS15 remains set until the PRE-RELEASE input is reinstated. MSS15 is used to monitor the PRE-RELEASE/RELEASE interval.
2.6.2        Second call during train phase
Following receipt of the PRE‑RELEASE input, if a second CALL is received prior to the controller being in the train phase intergreen period (i.e. the booms have moved off the horizontal but the controller is still not in the train phase intergreen) then the train phase sequence should be recommenced as per 2.1 above.
2.6.3        Second call during train phase intergreen
If a second CALL is received during the train phase intergreen period then proceed to the subsequent phase (but do not service pedestrians) and then commence a new train phase sequence as in 2.1 above.
2.7      RELEASE
The Release is indicated by the Release/Force input going to the on state. This indication releases the traffic signal controller to resume normal vehicle operation.  
3        SPECIAL PROCEDURES
3.1      ABNORMAL CONDITIONS
These conditions should not occur in normal operation. However, when they do, appropriate steps should be taken to register the event and to take action as follows.
3.1.1        Abnormal condition 1 ‑ Force before TLR
Although 35 seconds at least should elapse between receipt of a CALL input and the FORCE (termination of the R/F input), there may be occasions when the FORCE occurs prior to the controller issuing the TLR output. This will force a flashing‑yellow response and generate ABNORMAL CONDITION message No 1 via MSS3.  When the full RELEASE is received (the R/F input is reinstated) the controller will go through an all‑red start‑up sequence and resume normal operation.
3.1.2        Abnormal condition 2 ‑ Late Release
The RELEASE TIMER (Special Purpose Timesetting No 13.) commences counting from receipt of the PRE‑RELEASE.  If the R/F is not reinstated before expiry of this timer, then the controller will generate ABNORMAL CONDITION message No 2 via MSS4 and go to flashing‑yellow.  When the R/F input is reinstated, the controller will go through an all‑red start‑up sequence and resume normal operation.
3.1.3        Abnormal condition 3 ‑ Force without Call
If the R/F input is terminated without a previous CALL input, the controller will generate ABNORMAL CONDITION message No 3 via MSS5 and go to flashing‑yellow.  When the R/F input is reinstated the controller will go through an all‑red start‑up sequence and resume normal operation.
3.1.4        Abnormal condition 4 ‑ Break in Cable Monitor
If there is a break in the CABLE MONITOR input, the controller will generate ABNORMAL CONDITION message No 4 via MSS6 and go to flashing‑yellow until the CABLE MONITOR is reinstated. When this input is reinstated the controller will go through an all‑red start‑up sequence and resume normal operation.
3.1.5        Abnormal condition 5 ‑ Booms not Horizontal
If the BOOMS HORIZONTAL input is not received during the train sequence, the controller will generate ABNORMAL CONDITION message No 5 via MSS7. This flag is set at the start of the first phase following release from the train phase.
3.2      CALL TERMINATION TIMER
When a CALL input terminates prior to the FORCE (in the presence of the R/F input), a timer will begin to count down (Special Purpose Timesetting No.14).  Any further CALL inputs will reset the timer.  Once the FORCE is received (R/F terminated), the timer is ignored.  If the R/F input is not terminated prior to expiry of the timer, then the controller will AUTO‑RELEASE from the Track Clearance Phase sequence, proceed to Train Phase and resume normal vehicle operation. The purpose of this facility is to prevent the traffic signal controller from being "locked up" indefinitely by spurious inputs (in the case of automatic track circuits) or by inadvertent or excessively early calls (in the case of manned signal‑boxes).  
3.3      OPERATING MODES      
3.3.1        Isolation conditions
When the CALL input is received, the MSS1 flag is set and will instruct the regional computer (via VP routine 30) to force the controller into Isolated operation.  During this time the MSS1 flag will remain on until the termination conditions are met, for compensation to traffic delayed by the boom closure. The compensation sequence is detailed below.  
3.3.2        Compensation techniques
Once the train is clear of the crossing and the booms have raised to approximately 60 degrees, the RELEASE is indicated by the R/F input going ON.  At this point, the traffic signals should start in CØ, which allows traffic to cross the rail tracks.
If the site is running Isolated or Flexilink when the CALL input is received, MSS1 flag will stay on until the start of CØ intergreen (after the train phase). If the site is running Masterlink when the CALL input is received, MSS1 flag will stay on until the start of EØ intergreen.
CØ uses its own phase extension green after the train phase.
3.3.3        Resumption of dynamic mode
At the start of the TRAIN PHASE the MSS2 flag is set and will stay on until the start of the intergreen of the train phase.  The termination of the MSS2 flag is used to determine the moment at which the cycle generator is to be set for Masterlink operation.
3.3.4        Flexilink operation
Flexilink is permitted to run.
4        MSS FLAGS ‑ SUMMARY OF OPERATIONS
   4.1  MSS1
This Flag is SET upon receipt of the CALL and is used to force the site into isolated operation.
This Flag is DROPPED to allow the Local Controller to pick up Flexilink or Masterlink operation. (See 3.3.1)
   4.2  MSS2
This Flag is SET at the start of the TRAIN PHASE green.
This Flag is DROPPED at the start of the TRAIN PHASE intergreen and is used to SET the cycle generator in preparation for picking up co‑ordination in dynamic mode.  (See 3.3.3)
4.3 MSS3 to MSS7
These are described under ABNORMAL CONDITIONS.   (See Section 3.1.1 to 3.1.5)
4.3 MSS13, MSS14 & MSS15
MSS13, MSS14 and MSS15 are used to monitor the BOOMS HORIZONTAL input, the RELEASE/FORCE input and PRE-RELEASE input, respectively.
4.4    MSS11
MSS11 is set from the point when the CALL is deemed established until the CALL is removed.
5           VARIATION PARAMETER TABLES
5.1    Send Site Isolated
VP1  = 5    ‑ test MSS
VP2  = 0    ‑ current slot
VP3  = 1    ‑ MSS flag
VP4  = 30   ‑ send Isolated
5.2    Set Cycle Generator
VP5  = 5    ‑ test MSS 
VP6  = 0    ‑ current slot
VP7  = 2    ‑ MSS flag
VP8  = 20   ‑ reverse condition
VP9  = 53   ‑ set cycle generator    
VP10 =      ‑ value 
5.3    Abnormal Condition Message No 1
A:  "DCL 6120 RAIL LINK: FORCE BEFORE TLR
VP11 = 5    ‑ test MSS 
VP12 = 0    ‑ current slot
VP13 = 3    ‑ MSS flag
VP14 = 36   ‑ read TC file
VP15 = A    ‑ true TC data set A 
VP16 = 0    ‑ no action if false
5.4    Abnormal Condition Message No 2
B:  "DCL 6120 RAIL LINK: LATE RELEASE
VP17 = 5    ‑ test MSS 
VP18 = 0    ‑ current slot 
VP19 = 4    ‑ MSS flag
VP20 = 36  ‑ read TC file
VP21 = B    ‑ true TC data set B
VP22 = 0    ‑ no action if false
5.5    Abnormal Condition Message No 3
C:  "DCL 6120 RAIL LINK: FORCE WITHOUT CALL
VP23 = 5    ‑ test MSS 
VP24 = 0    ‑ current slot
VP25 = 5    ‑ MSS flag
VP26 = 36   ‑ read TC file
VP27 = C     ‑ true TC data set C
VP28 = 0    ‑ no action if false
5.6    Abnormal Condition Message No 4
D:  "DNC 6120 RAIL LINK: BREAK IN CABLE MONITOR
VP29 = 5    ‑ test MSS 
VP30 = 0    ‑ current slot 
VP31 = 6    ‑ MSS flag
VP32 = 36   ‑ read TC file
VP33 = D    ‑ true TC data set D
VP34 = 0    ‑ no action if false
5.7    Abnormal Condition Message No 5
E:  "DNC 6120 RAIL LINK: BOOMS NOT HORIZONTAL 
VP35 = 5    ‑ test MSS 
VP36 = 0    ‑ current slot 
VP37 = 7    ‑ MSS flag
VP38 = 36   ‑ read TC file
VP39 = E    ‑ true TC data set E
VP40 = 0    ‑ no action if false
APPENDIX 2
STANDARD RAIL LINK CABLE TERMINATION CHART
FOR CONTROLLERS WITH RELAY OR SOLID-STATE LOAD-SWITCHING
SITE:  NUMBER: 
MUNICIPALITY:     DESIGNER:     DATE: 
* Delete the inputs and or outputs on this page which are not used.
RAIL-LINK NO-TRAIN PAIR CONDUCTOR TERMINATION DETAILS
DESCRIPTOR CIRCUIT REF. INSULATION
or FUNCTION           STATUS   No.    COLOUR                                                  
CABLE MONITOR CLOSED 1st WHITE --------- DET. RETURN
(CONTINUITY) BLUE ----------- DETECTOR NUMBER:  13
PRE-RELEASE CLOSED 2nd WHITE --------- DET. RETURN
     (FGR) ORANGE ------ DETECTOR NUMBER:  14
RELEASE/FORCE CLOSED 3rd WHITE --------- DET. RETURN
(R/F or FCR) GREEN --------- DETECTOR NUMBER:  15
CALL OPEN 4th WHITE --------- DET. RETURN
BROWN -------- DETECTOR NUMBER:  16
BOOMS OPEN 5th WHITE --------- DET. RETURN
HORIZONTAL GREY ----------- DETECTOR NUMBER:  17
SPARE OPEN 6th RED ------------- NOT TERMINATED
BLUE ----------- NOT TERMINATED
SPARE OPEN 7th  RED ------------- NOT TERMINATED
ORANGE ------ NOT TERMINATED
SIGNALS OFF OPEN 8th RED ───────────────────┐
(FY or BO) GREEN ───────────►◄────┘ (NC) "FLASH" RLY
ACKNOWLEDGE OPEN 9th RED ───────────>  <────┐ (NO) "A" RLY
CALL  (AKN) BROWN ─────────►◄─────┘ (NC) "B" RLY
TRAFFIC LIGHT OPEN 10th RED ───────────>    <──── (NO) "A" RLY
RESPONSE  (TLR) GREY ──────────>    <──── (NO) "B" RLY
For solid-state load-switching, suitable termination is as follows:
ACKNOWLEDGE OPEN 9th RED ─────────►◄────────┐ (NC) "RED" RLY
CALL (AKN) ┌─────►◄───────┘ (NC) "YEL" RLY
└─────►◄───────┐ (NC) "GRN" RLY
BROWN  ────────────────┘
TRAFFIC LIGHT OPEN 10th RED ───────────────────┐
RESPONSE  (TLR) GREY ────────>    <────── (NO) "GRN" RLY
§         "TLR" (and "AKN" outputs are driven by SIGNAL GROUP NUMBER:_____10____________ using the "RED", "OFF", "GRN" and "YEL" logic states as shown in the TYPICAL SEQUENCE CHART.
§         The (AKN) output may be required occasionally (for manual operation at signal-box sites) thus requiring installation of the "RED" and "YEL" 240 V relays in addition to the "GRN" 240 V relay.