MCB – OD Basic Description, Equipment, Layout, Operation and Circuit Flowchart This document is not endorsed by Network Rail. It is NOT for installation, commissioning, testing or maintenance purposes, it is for information only. Network Rail’s own documents must be followed at all times. REMEMBER this is uncontrolled and therefore any measurements stated may have changed to the current standard. Consult NR documents before any work takes place. ©Copyright F. M. Spowart Page One of Thirteen Version Two: May 2015 MCB – OD Page Two of Thirteen Basic Description of MCB – OD system: The MCB OD system was introduced for two main reasons. Conventional MCB’s using CCTV require the signaller to confirm that the crossing is clear. There have been a few instances where the signaller has ‘confirmed’ that the crossing was clear, when in fact it was not, resulting in near misses and a collision. This is primarily down to lack of concentration when trying to control other crossings and trains as well. The other reason is due to many signalboxes being closed and transferred to ROC’s (Rail Operating Centre’s), and with these closures, many CCTV controlled crossings would become too much for a single ROC to handle, so crossings would need to be automated. As half barriers are subject to abuse by road users, full barriers are now preferred. This is where the MCB – OD (Obstacle Detectors) are now the ‘eyes’ on the crossing. Used elsewhere in Europe, they have been a success. However, other countries only use a primary RADAR to detect vehicles. Pedestrians are not accounted for except in the UK where it is a legal requirement. Therefore, as well as a primary RADAR called a POD (primary obstacle detector) to detect vehicles, we have a high-level complimentary LIDAR called a HL COD (complimentary obstacle detector) to detect adult pedestrians. As well as the high-level (HL)COD, some crossings, subject to a 9-day census, may have a low-level (LL)COD where the crossing is used by children frequently. All UK crossings as a minimum have a POD and a HL COD. ALL the RADAR’s and LIDAR’s MUST confirm that the crossing is clear before signals will be allowed to clear. The POD has two multiprocessors that must be in agreement before it allows a crossing clear confirmation; this is classed as a ‘SIL3’ interlocking (similar to an SSI interlocking). The POD uses reference reflectors (RR) (triangular mirrors) to determine the area under surveillance as it scans a 140 degree area. If the POD cannot not see all the RR’s, it will never give a crossing clear. The actual (target) area of the crossing is set-up using the on-site PC using reference markers and angles inputted into the system. All RADAR’s and LIDAR’s (PODS & CODS) are set-up using a very lengthy process that could take up to three days to complete per crossing. Level one staff are trained to maintain and fault the equipment and make minor adjustments to the reference reflectors. Only level two staff are trained to adjust and set-up the equipment. Under NO circumstances should level one staff alter any other settings than what they are trained to do, or the RADAR’s could be damaged/moved and give a false crossing clear. The POD cover shouldn’t have to be removed by level one staff. Serious damage could occur to the moving RADAR inside and render is out of action. The POD’s alone cost in the region of £60,000. The LIDAR screens are now protected by automatic electric shutters that keep them clean during idle mode. Note: during auto OD operation, all personnel, MUST be outside of the detection zone (the crossing deck, and outside of the barriers), and behind all COD’s and reference reflectors or a false obstacle WILL be detected and stop signals from clearing and fail the crossing. MCB – OD Page Three of Thirteen On-site crossing clear (CC) and LCU controls (for maintenance, faulting or failure): LCU: Two control pedestals are provided at the crossing. One is a normal LCU unit which provides control of the crossing during complete failure, maintenance or engineering work. CCU: The other pedestal contains the CCU (crossing clear unit) controls. If the OD’s fail and crossing clear cannot be confirmed by the RADAR and LIDAR’s, then a level crossing attendant (LXA) will be called. Inside the unit is a three position switch, (left for all signals on, middle for normal (auto) and right for CCU mode). In CCU mode and once all the barriers are detected down, two buttons will flash. The LXA will then confirm CC by sight and then push BOTH buttons to confirm this. Signals will then be able to clear. All signals on is used if an incident then happens after CC is confirmed. Note: earlier CCU’s were called ‘XCU’s, but should now all be changed. Basic operation: The actual crossing circuits in the MCB – OD are very similar to that of a conventional MCB, but many new relays have been added to do with the OD part. The crossing sequence is started by a train striking-in and the ‘minimum road open time’ applies. Roughly at the same time, the POD and COD’s (named as detectors from this point) activate and selftest (6-7 seconds) and the COD shutters lower (2 seconds). After the ambers and red road lights, the entrance* barriers come down and the detectors scan the crossing. After scanning and confirming crossing is clear (CC), the exit barriers fall after the 10 second antitrapping* feature (the time given to allow any vehicles or pedestrians to escape if they happen to be trapped by the entrance barriers). *On two barrier operation, this is not applicable. Once the exit barriers have lowered, the detectors scan the crossing. The POD scans three times to confirm. The COD’s also confirm crossing clear. Once all detectors are in agreement they are given a STOP command and their outputs are frozen (just as the picture goes blank with CCTV crossings) and the signal will clear. Note: Between the DN KR(2) picking and the last clear scan, (OD)(SCAN) JPSR (4 second timer) will pick and then pick the (CC)SR and only then confirm that the crossing is clear. The shutters on the COD’s come up after CC confirmation. If however, the exit barriers come down (or all if two barrier operation) and then an obstacle is detected within four seconds, they will raise themselves. The RADAR detectors will continue to scan the crossing. The failure to give crossing clear is registered with interlocking (ABM(2) relay) and a second attempt will commence (ABM(3) relay). If a second attempt has proved unsuccessful, again registered by the interlocking (ABM(4) relay), the exit barriers will raise and no longer be in automatic mode and will effectively ‘fail’ in the air, although this is not technically a failure and an object has been seen by the detectors and have therefore done their job. If this happens, intervention will be required by the signaller (he will be given indications saying that an obstacle has been detected). He will be required to lower the barriers by button then after having red roads confirmed lit, all barriers intact (BOOM CR) and down indication, they will caution the train passed the red signal. Note: Under NO CIRCUMSTANCES will the BOOM CR be strapped out at any time. MCB – OD Page Four of Thirteen Once the train has passed, the barriers will be required to be raised by the signaller and then the crossing will reset. It will then require the S&T to go out and determine the cause of the detection whether false or not. Critical failures of the RADAR POD will result in the (OD F2)SR relay dropping and failing the crossing. If this happens, the POD will require powering down, waiting for one minute, powering back up, waiting one minute and then the OD RESET button pressing to reset the (OD)(CYC)SR. It will then take approx 30-40 seconds to respond to commands. Barrier Protection Management (BPM): On some crossings where they are close to road junctions where there may be a risk to ‘blocking back’, a system called BPM (barrier protection management) is used. This is where one or more of the barriers may fall onto a queuing vehicle and therefore rip it off. To overcome this, sensing wires are cut into the road surface under where the barrier will fall and if triggered will stop the barrier from lowering AND its opposite one too. BPM indications are provided to the signaller should it be triggered. Once the vehicle(s) moves clear, the barriers will lower as normal. DVR, Recording Equipment and ‘Dropbox’: All OD crossings are equipped with HD video monitoring equipment including red light cameras and ANPR cameras and a ‘SA380’ datalogger. Both are recorded 24hrs a day onto a DVR. The DVR also records Redscan (LIDAR COD files) and RWMON (RADAR POD files). Not only do these provide evidence of possible mis-use and incidents, they are also used to aid in fault finding, for example a false or real obstacle detection that stopped a crossing clear being given. A storage system called Dropbox is used at all crossings that enable video footage, datalogger files, Redscan and RWMON to be downloaded to it and then any person logged in Dropbox will be able to view them to either prove a failure or for another technician nationwide to read the files and determine a cause. Files must be downloaded on site to Dropbox to enable remote viewing. Videos from the DVR can only be viewed from a PC. All other files can be viewed via a PC or an i-Device, such as an iPad or iPhone, (app downloaded from the Apple App Store). Dropbox also contains site specific information, OD manuals and the signallers fault finding (FF) guide. On no account should any files be deleted from Dropbox unless it was you who originally posted it and it is no longer required. DVR files are deleted after 48 hrs so it’s imperative that any evidence is gathered immediately and stored on to Dropbox should any allegation be made. For security reasons, Dropbox log-in details and email addresses are not listed on here. MCB – OD Page Five of Thirteen Basic crossing equipment layout and brief description: Note: this must be viewed in colour to appreciate diagram below ˃1.5m ˃4m ‘COD B’ REB A B ˃2.5m ‘COD A’ 2 to 3m 140 degree Scan area of the POD Equipment/key Brief Description RADAR primary obstacle detector (called the ‘POD’). Rotating dish inside that scans the crossing at 140 degrees known as the surveillance area. Its primary function is to detect vehicles on the crossing. The actual area detected is set by the reference reflectors (see below). LIDAR complimentary obstacle detector (called the ‘COD’). Primary function is to detect objects that the POD cannot detect, such as people. Comprises of either one high level (HL) LIDAR at all times (two minimum per xing). A low level (LL) LIDAR (two minimum per xing)is fitted when the crossing is frequently used by pedestrians. Can have up to 6 CODS (12 in total; 6x HL & 6x LL Lidars). The reference reflectors (or known as corner reflectors). They do not however define the corners. They are fixed into position and are used as a reference to where the POD scans to determine the detection area. Anything outside this area is disregarded. Scanned area of the HL LIDAR of COD A. This is to within 25mm of the nearest barrier. It overlaps the scanned area by COD B and covers the whole area within the crossing and 25mm short of the nearest barrier. Scanned area of the HL LIDAR of COD B. This is to within 25mm of the nearest barrier. It overlaps the scanned area by COD A and covers the whole area within the crossing and 25mm short of the nearest barrier. MCB – OD Page Six of Thirteen Scanned area of LL LIDAR of COD B. The scanned area covers the deck of the crossing, usually to the edge of the BOMACS; (660 – 780mm from the running edge of the rail) Scanned area of LL LIDAR of COD A. The scanned area covers the deck of the crossing, usually to the edge of the BOMACS; (660 – 780mm from the running edge of the rail) The Radial Non-Detection Zone. This is a 2 – 5m zone to ensure reliability during falling snow or heavy rain etc. Even though the nearest COD has its own nondetect zone, the furthest one will detect any objects. A B CCU: Crossing Clear Unit. This is equipped with a three position switch for SIGNALS ON/NORMAL/CROSSING CLEAR. ‘Signals on’ puts all signals to red. Crossing clear enables a LXA to override the OD’s and observe crossing clear and depress two buttons below to confirm. This is for either OD failure or whilst crossing testing/observation of software. LCU: Local Control Unit. For use to operate the crossing fully when it has either failed completely or when engineering works on or near crossing. Note that this has a two minute timer that will render it non-controllable after first being opened, only if the RAISE button is required. The detection zones. As seen on the PC in the REDSCAN program. These zones are labeled B2, B1, A1 and A2. The buffer zone. This is the area that must be free from fixed objects, such as pedestals, lighting columns, fences etc etc. The crossing deck known as the target or surveillance area. 1 metre from the barriers or any trackside furniture such as lighting columns etc. Brief description of levels and measurements: The RADAR (POD): RADAR BEAM: Min: 2m max: 60m C3 Radar Heights: C1: 50min (+22)cm C2: 50 +5/-2cm C3: 50min (+28)cm 140x1 degree tranches C2 Deck C1 Follows crossing 1m from barrier & crossing furniture MCB – OD Page Seven of Thirteen The Reference Reflectors: Max: 90 degree angle Less than 60m away (top of base): 20mm below the nearest rail head. (SPT base used) Middle of bracket to base starting height: 880mm (final height determined on set-up) The LIDAR’s (HL & LL COD): Distance from COD to anti-trespass guards: 460mm Max 20.4m range from centre of post 2 to 5m non-detect zone (LL) Height of laser from deck: LL LIDAR (children frequently use crossing): 100 to 175mm LL LIDAR: (adult frequently use crossing): 130 to 280mm Absolute minimum is 100mm. Deck (HL) Height of laser from deck: Min top of beam height: 390mm Max bottom of beam height: 610mm Note: LL heights should be as close as possible to maximum height levels as stated. MCB – OD Page Eight of Thirteen The operating system: The MKII DVR and the PC are housed in an REB next to the crossing. Several passwords are required to enter the DVR (MKI only), RADAR and LIDAR programs for taking readings or making observations only. Settings must not be altered by staff without the set-up (Level 2) competence. Passwords: The Mark I DVR ONLY (all these should have been upgraded to Mark II): Username: 1 Password: 1 To access the RADAR program called ‘RWMON’ on the PC: Username: None (not applicable) Password: H*******L (all uppercase) To access the LIDAR program called ‘REDSCAN’ on the PC: Username: R*****N (all uppercase) Password: O***X (all uppercase) The RADAR & LIDAR program passwords are not all shown for security reasons. To access the RADAR (POD) program (RWMON) for maintenance purposes: Important: you must ask signaller for permission and put crossing onto CCU mode in pedestal before entering software programs or crossing will show failed. To open program: 1. Open ‘RWMON’ from desktop, and click OK. 2. Question asked ‘reconfig required’. 3. Select ‘Nein’ (no). 4. Select ‘Program’. 5. Choose ‘Password’. 6. Enter Password (see page above). 7. Select ‘OK’. 8. Choose ‘Configuration’. 9. Select ‘Create/change GFR’. 10. Choose the “active GFR file”. 11. ‘CRC checksum’ appears, ‘OK’ it. 12. ‘OK’ the next menu (Note; this contains info for the record card). 13. Choose ‘Configuration’ 14. Select ‘Test Mode Target Display’. Test mode target display appears. To remove the blue crosses to give a clear edge of the surveillance area, choose ‘Options’ and then select ‘Corner Points’. To Close the RWMON program: Important: you must follow these instructions, or the crossing will not return to auto mode. 1. Select ‘Configuration’ 2. Choose ‘Test Mode End’ 3. Select ‘Program’. 4. Choose ‘End’. 5. Confirm by selecting yes. 6. If you are in CCU mode, put switch back to normal and close the door. 7. Confirm with signaller that crossing is showing auto. MCB – OD Page Nine of Thirteen To access the LIDAR (COD) program (Redscan) for maintenance purposes: To open the Redscan program: 1. Select ‘Redscan’ from desktop. 2. When open, in small window on the left, select the LIDAR you wish to view. 3. Select ‘Connect Detector’ in the top left. 4. Once active, tick box called ‘Vertical’ to give a true view from the COD. The scanned area will give information on how it is set up. Objects in detection area will show up as a white circle with a RED outline, these will ‘occupy’ the OD. Objects outside the detection area that will not occupy the OD will show up as white circles with BLUE outlines. To close the Redscan program: 1. Select ‘Disconnect Detector’. 2. Close the program. 3. Confirm by selecting ‘Ja’ (yes). 4. If you are in CCU mode, put switch back to normal and close the door. 5. Confirm with signaller that crossing is showing auto. Using Dropbox to store POD error files: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. Open RWMON program (see page five). Select ‘Configuration’. Select ‘Protocol Data’ at bottom. Click Document button in middle (C:\Documents and Settings….). Select ‘My Documents’. Select ‘Dropbox’. Choose crossing name if applicable. Select ‘Support Files’. Choose RADAR you want to view; POD or COD. Enter a date and time in this format: YYYY.MM.DD_TTTT (For example: 20150518_0935). Open Select at top ‘Protocol’ or ‘Error’ memory to view. Select ‘Start’. Note: if Protocol is selected, it will count the memory blocks (wait). ‘CRC checksum’ appears, click OK. View files. Choose ‘End’. Close window in normal way. Use Windows START button > My Documents > Dropbox to check files have stored. Notes: Reset memory button on step 12 erases last error memory. In window in step 15, “TAR” means the number of pixels the RADAR cannot see, so the higher the number the bigger the object. “CNR” means the number of reference reflectors seen by the POD. Capturing Redscan screenshots of the LIDAR’s and saving to Dropbox: 1. 2. 3. 4. 5. 6. 7. 8. Open REDSCAN program (see above). Choose LIDAR from window on left. Select ‘Window Capture’. Select ‘Save’. Select ‘Dropbox’ file in My Documents. Name the file in this format: YYYY.MM.DD_TTTT (and the crossing name). Check in the ‘Dropbox’ folder in My Documents that screenshot has saved. Close Redscan program (see above). MCB – OD Page Ten of Thirteen Circuit Flowchart: Crossing is set to AUTO with correct indications for the OD’s to work Train occupies strike-in TC on approach TPR drops TAR picks 20 SECOND TIMER STARTS FOR (A LOW) JR & AFTER 20 SECS... 10 SECOND TIMER FOR (MROT) STARTS & AFTER 10 SECS... This is the minimum time between trains striking in on opposite lines to ensure vehicles and pedestrians have time to exit (MROT) picks (A LOW) JR picks LOWER SR drops YODALS START SOUNDING CON SR drops 1st attempt at closure recorded (ABM)SR (1) drops (OD) (START) SR picks (OD) (RUN) picks HER drops AMBER ROAD LIGHTS LIT (OD)ZR drops (LL COD A) (FRE A) R picks AFTER 3 SECONDS... HJR drops HJPR drops AFTER 5 SECONDS... (LL COD A) (FRE B) R picks (LL COD B) (FRE A) R picks (LL COD B) (FRE B) R picks RECR picks RED ROAD LIGHTS FLASH RECPR picks (if no lamps failed) (CON)JPR drops LOWER R(1) drops (POD) (ACT B) R drops (POD) (ACT A) R picks (CON)JR drops (UP) KR drops ENTRANCE BARRIERS LOWER (POD) (ACT A)SR picks (POD) (ACT B)ZR picks A (A LOW) JR drops DN KR(1) PICKS (MROT) drops B MCB – OD Page Eleven of Thirteen B A (POD) (FRE B)R drops (POD) (FRE A)R picks (POD) (FRE A) SR picks (POD) (FRE B) ZR drops NO OBSTICLE DETECTED THROUGHOUT (TO (OD)(SCAN)JPSR PICKING) (OD) (CLR) R picks (OB.D) SR picks Box F (LOWER) (2) CR drops Refer to these relay conditions when the OD’s are scanning and have not detected an obstacle. (LOWER) R (2) drops (LOWER) (2) JR STARTS TIMING AFTER 10 SECONDS... (LOWER) (2) JR drops EXIT BARRIERS LOWER (DN) KR (2) picks OBSTICLE IS THEN DETECTED YODALS STOP SOUNDING (DN)SR picks (BARRIERS PROVED DOWN & LOCKED) (OD) JR picks AFTER 4 SECONDS... (OD)(SCAN) JPSR picks E (CC) SR picks (xing confirmed as clear) XZGR picks (OD)STOP SR picks ALL CONDITIONS MET: signal clears (OD) START JR STARTS TIMING AFTER 3 SECONDS... (OD) START SR drops (OD) (CLR) R drops (OD) RUN JR drops (OD) (STOP) SR STARTS TIMING AFTER 3 SECONDS... (OD) (STOP) SR drops A B (OD) ZR picks (OD’s Idle mode) MCB – OD Page Twelve of Thirteen A B The POD and/or COD relays pick and drop according to which RADAR/LIDAR has seen the obstacle. (POD) (FRE A) SR drops TRAIN PASSES THROUGH AND ACTIVATES XASR & XUSR IN SEQUENCE, AFTER ALL CONDITIONS MET, THE (CON) SR RE-PICKS AND CROSSING RETURNS TO NORMAL. (This is the same as normal MCB crossings. (See MCB notes). (OD) (CLR) R drops (OB.D)SR drops Z (RAI) SR(2) picks 1st closure failed (ABM)SR(2) drops (ABM)YJR starts timing 1 of 2 Stick paths for (ABM)SR(3) lost EXIT BARRIERS RAISE RADARS RE-SCAN CROSSING (ABM)YJR has started timing. After 30 seconds, and after Z(RAI)SR(2) has repicked, it will hold it up preventing any further attempts to reclose the crossing & CLEAR (NO OBSTICLE) Relay conditions as above (see box F) (OD) (CLR) R picks (OB.D)SR picks Z (RAI) SR(2) drops (ABM)SR(3) drops 2nd closure attempt recorded If crossing remains clear 4 seconds after exit barriers are down the (OD)(SCAN)JPSR picks. Go to box ‘E’ above and continue. EXIT BARRIERS DROP RADARS RE-SCAN CROSSING A MCB – OD Thirteen of Thirteen A The POD and/or COD relays pick and drop according to which RADAR has seen the obstacle. OBSTICLE DETECTED (OD) (CLR) R drops (OB.D)SR drops Z (RAI) SR(2) picks (ABM)SR(4) drops EXIT BARRIERS RAISE Alarm to signaller. He will need to lower on button Two closures failed. AUTO function is now lost, no more attempts to close crossing will be made. Signaller selects LOWER LOWER NPR picks (ABM)ZR picks Z(RAI)SR(2) drops EXIT BARRIERS LOWER SIGNALLER CAUTIONS TRAIN ACROSS THE CROSSING After the train has passed, and no others are approaching, the signaller will raise barriers on manual. LC will reset as it had seen a obstacle and not a fault. Technician will have to observe detection area and determine the cause. Copyright F. M. Spowart May 2015 Version Two
© Copyright 2024