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| Axle Counter Controls 31/03/2015 at 07:50 #70558 | |
Firefly
521 posts |
I was chatting with Hooverman at work the other night and we were discussing how introducing axle counter controls would add another dimension to Simsig. I think it would probably be too much work for the Devs, however it would be good. For the uninitiated, axle counters are replacing track circuits nationwide and there are a few differences to track circuit operation. Under normal running there is no difference, an occupied section show red and replaces signals etc just like a track circuit. They do however have a few other features. Firstly it's possible to reset a failed axle counter section if it's only +1 or -1 axle. It's assumed that for some reason the system missed an axle and the signaller can reset it (albeit with a bit of form filling and double checking) Once reset you will have an aspect restriction across the relevant section. This means that signals will not show a proceed aspect across the section until 1 train has traversed the section (inspected the line). Secondly in the case of engineering works the signaller should apply EPR's to all of the axle counter sections within the possession. An EPR is an Engineers Possession Reset and it allows the axle counter to be reset regardless of what the count is. (You may have had road rail machine or trolleys which have just up sticks and left the railway leaving the axle counter section with many axles in section). The EPR must be put on prior to the axle counter section showing occupied and you cannot clear a signal over a section which has an EPR applied. Finally there's STR which is a special train reset and this can be applied for trains which are not guaranteed to operate the axle counter sections. It's similar to EPR. Older systems had different styles of reset some require both technician and signaller simultaneous inputs. Not many people/hosts simulate possessions so the EPR may not be much use, however the failure with resulting aspect restriction would get used with random failures. FF Last edited: 31/03/2015 at 09:05 by Firefly Log in to reply |
| Axle Counter Controls 31/03/2015 at 09:45 #70560 | |
flabberdacks
636 posts |
Speaking as an uninitiated: Would this mean there'd be a a few buttons next to every signal for the appropriate overrides? How do these controls work in actual signal boxes, i.e. where are they located, how would they display a +1/-1? What kind of advantages do axle counters provide over track circuits, that would lead them to render TCs obsolete? I can understand for a one-train working section or similar, but not sure beyond that Log in to reply |
| Axle Counter Controls 31/03/2015 at 10:19 #70561 | |
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Firefly
521 posts |
Quote:Speaking as an uninitiated: Would this mean there'd be a a few buttons next to every signal for the appropriate overrides?There's a dark red roundel next to every axle counter section on VDU systems. On Panels there's a button.   Quote: How do these controls work in actual signal boxes, taking IECC as an example as per the photo above the Signaller presses the button for the section that needs resetting (it illuminates red). They then have to type the axle counter name as confirmation, the roundel flashes whilst the system works and if successful the section will go clear but will have a Dark Red border to signify that there's an aspect restriction. (on panels there's an aspect restriction indication next to each signal) There's nothing to tell the signaller if it's a +1/-1 count or some other problem so standard procedure is to try and reset and if that works - happy days. If it doesn't work call out the S & T To apply/remove EPR's STR's there are buttons at the bottom of the screen. Press EPR then Press the roundel next to the track circuit you wish to apply the EPR on. To remove EPR, press EPR, Cancel the roundel and then type in the axle counter name as confirmation. On panels there's a Reset and EPR button but they don't have STR.   On the top picture EPR is applied to TDCV which is why it has a grey border. If it was aspect restricted it would be a dark red border. Quote: What kind of advantages do axle counters provide over track circuits, that would lead them to render TCs obsolete? I can understand for a one-train working section or similar, but not sure beyond thatThey don't suffer from ballast resistance problems or dodgy insulation on sleepers, they don't have length restrictions, you can use all rails for traction return without the need for impedance bonds, you don't need to install insulated rail joints which are expensive and have a lifespan. On the down side many people don't like them because they cannot detect a rail breaks (often but NOT always track circuits fail with a broken rail), you can't use track circuit operating clips on them (but nor can you in a absolute block section) and there have been reliability issues. From an interlocking point of view there is a heck of a lot more programming and testing required. FF Post has attachments. Log in to view them. Log in to reply The following users said thank you: Steamer, flabberdacks |
| Axle Counter Controls 31/03/2015 at 10:42 #70564 | |
Steamer
3985 posts |
Another question from the uninitiated: How do axle counters work? Is it a light-gate (wheel breaks beam, counter counts number of breaks), a mechanical switch operated by the flange, or something else? "Don't stress/ relax/ let life roll off your backs./ Except for death and paying taxes/ everything in life.../ is only for now." (Avenue Q) Log in to reply |
| Axle Counter Controls 31/03/2015 at 10:52 #70565 | |
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Firefly
521 posts |
I don't know too much of the inner workings of them but basically they detect metal on the top of the rail. (Yes I realise the rail is already metal) There's a transmitter and receiver at the axle counter head which forms an eltromagnetic field on the railhead. An axle or (Pway mans shovel!) being passed over the sensor destroys the field so the receiver loses it's input. There are a pair of these sensors at each axle counter head so they can tell which direction the axle is going. There's an evaluator unit which holds and evaluates the count information. There's a bit of information on Wikipedia that seems fairly accurate. FF Log in to reply The following user said thank you: Steamer |
| Axle Counter Controls 31/03/2015 at 12:45 #70570 | |
madaboutrains
316 posts |
Are those panel pictures of Basingstoke?
RIP Feltham Panel 1 Log in to reply |
| Axle Counter Controls 31/03/2015 at 12:58 #70572 | |
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Firefly
521 posts |
Quote:Are those panel pictures of Basingstoke?Yes Poole to Wool panel. FF Log in to reply |
| Axle Counter Controls 31/03/2015 at 17:51 #70584 | |
Mattyq
259 posts |
Axle Counters have been used here in Australia for many years, however, their treatment and application differ to what I'm reading here with UK axle counters. Queensland:- Axle counters will show a track occupied after a count-in just like a track circuit. Like UK, you do not actually receive data at the Signallers level about how many axles are counted into and/or out of each section. Depending on the brand of axle counter, different things may occur after an axle count mismatch. In all cases, it will leave the section showing occupied after a count-out mismatch. Some will also generate an alarm, others won't. In QLD, in order for the Signaller to reset an axle counter, the last "transaction" must have been a count-out (IE: train leaving the section). QR does not apply a +1/-1 tolerance, therefore, a reset is possible after any mismatch, so long as a count-out has been registered. The following, again, depends on the brand of axle counter:- At some locations, the act of resetting is performed solely by the Signaller, but must be witnessed by a person in charge who notarises the Signallers TR book/graph. At some locations, the act of resetting must be performed simultaneously by the Signaller and a person in charge. The latter still notarises the Signallers TR book/graph. At some locations, the act of resetting must be performed by the Signaller and a person in charge in sequential steps. The latter still notarises the Signallers TR book/graph. QR axle counters do not have EPR/STR functionality. Unfortunately, it is necessary to call S&T for a reset after engineering works, track machines being lifted off mid-section or any failure where a count-out was not registered. QR axle counter systems do not impose a restricted aspect on the first train to enter the section after a reset, however, this procedure is covered at an administrative level (IE: rules and procedures). In actual fact, the greater bulk of axle counters used in QLD are on long section where the entry signals can only show Red or Green, a restricted aspect not being possible. NSW:- I cannot speak for axle counters used in ARTC or Railcorp ("Sparky" might wish to weigh in here?), only those in the "Country Regional Network (CRN)". The line from Lithgow to Orange and Baal Bone Jn is signalled but all is track circuited. All of the rest of the CRN operates under Train Order Working with no rail vehicle detection system. Axle counters are only used for rural level crossings, especially those with infrequent services. Track circuited level crossings generate a "No trains 72hrs" alarm if a train has not crossed it within a 72hr period causing rust build-up on the rail head. Axle counters alleviate this problem. All of these axle counters can only be reset by S&T staff. Note to "Flabberdacks", I seriously doubt axle counters will ever completely replace track circuits. Not fat ..... fluffy!! (G Iglesias) Last edited: 31/03/2015 at 17:56 by Mattyq Log in to reply |
| Axle Counter Controls 31/03/2015 at 19:21 #70588 | |
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clive
2789 posts |
" said:Apart from the reasons already listed, it's possible to arrange things to cope with a failed counter. Suppose you have adjacent sections A and B with axle counters P, Q, and R (Q at the boundary between A and B). If Q fails to count for reason, but the number coming into A at P equals the number coming out of B at R, it's possible to reconfigure things to merge A and B into a single section. (The counters all feed back to a calculation unit that handles many sections at once, so this is pretty trivial to do.) I don't know if this is done anywhere in practice, but it's certainly possible and it was touted as an advantage. Log in to reply |
| Axle Counter Controls 31/03/2015 at 20:26 #70590 | |
Guts
604 posts |
It can add realism but I think it should be an option as with the Level Crossings on Feltham. I say this because though it increases the realism it makes it hard be in control of the whole Sim, especially for newbie who don't or can't join online sessions Log in to reply |
| Axle Counter Controls 31/03/2015 at 21:21 #70592 | |
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Muzer
718 posts |
So what do you do when there's an issue involving more than 1 axle? Do S&T reset the counters in some way directly?
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| Axle Counter Controls 31/03/2015 at 22:54 #70594 | |
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Hooverman
306 posts |
I was thinking as sims get developed and redeveloped they will increasingly cover areas that are now have train detection via axel counters. So instead of haveing a failed track circuit you could have a failed axel counter section, that would require a reset, sweeper train to restore it back to the interlocking using aspect restriction and indication of resticted route. All sounds pretty complicated but I think that the average SimSigger would pick it up fairly quickly and it means that you get to clear the failed axel counter section (track circuit) yourself as per the rules and not wait forever for the techs to turn up. Having said when you reset the axel counter section after it's been disturbed or it has miscounted it will hold the protecting signal at danger and you are required to get the first train to examine the line through the section to restore it back to the locking. But the good point is that once you've reset the section is that any points that were held can be moved either by IPS or by setting a route. The protecting signal will not clear as it becomes aspect restricted due the reset and by setting the route you get indication of restricted route thus negating the need to lock individual points. So the safety of the locking is provided but the signal will remain at danger until the first train has gone through the section which in doing so restores the axel counter section back to full signalling.
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| Axle Counter Controls 31/03/2015 at 23:04 #70598 | |
headshot119
4869 posts |
Back when I was developing North East Wales it was suggested that I add the axle counter reset for the branch to Wrexham Central, and I did try and code something bespoke but it didn't work particularly well and didn't make it into the release copy. It'd certainly clutter the screen a lot if you had a sim with lots of axle counter sections. It would be a nice feature though. "Passengers for New Lane, should be seated in the rear coach of the train " - Opinions are my own and not those of my employer Log in to reply |
| Axle Counter Controls 31/03/2015 at 23:44 #70601 | |
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Jay_G
54 posts |
Axle counters would add another dimension to SimSig! Bear in mind they can also completely fail all together and refuse to reset (ieequilment failure, power failure, cut cable etc) I'm not entirely sure axle counters will replace TCs in their entirety. Talking to a commissioning engineer, they are apparently not so good in busy, multi line areas. The evaluators are so good at working out what has gone where and how many axles! They are also not so good at lots of reversing, and trains stopping near them! Log in to reply |
| Axle Counter Controls 01/04/2015 at 09:56 #70604 | |
Giantray
347 posts |
" said:On the down side many people don't like them because they cannot detect a rail breaks (often but NOT always track circuits fail with a broken rail)...The reason why broken rails aren't always detected is because not all track circuits are double rail track circuits. Through S&C(point work) track circuits are single rail. If a rail breaks in a single rail track circuited area and it is on the non-track circuited rail, it will go undetected. Also some broken rails are not a clean break, some times part of the rail breaks away. As for Insulated Block joints, modern track circuits are frequency based and require no Insulated Block Joints and have tuned zones. The Thameslink Programme is using 'tuned zone' track circuits as opposed to axle counters. Because of the density of the area being resignalled, it would take too long to reset axle counters after the many engineering possession they have in the area. In Europe they have experiences five times better reliability of axle counters over track circuits, but do not use them in the majority of busy areas. Busy areas require large numbers of track circuit/axle counter detection. Places like North American use axle counters on many of their routes. Since axle counter detected sections are virtually limitless in length, they are ideal for low traffic areas such as freight only lines. The Signalling controlled by New Cross Gate OBC, on the London Overground Line, have axle counters. If anyone gets to visit the place, ask to see the book they have for resetting axle counters, it will then realised how long the process of resetting axle counters can be. There are pros and cons to both systems, as Jay_G says, axle counters will not entirely replace track circuits. As Guts says, if Axle counters are added to Simsig, a switch off function would be required. The functionality of Simsig is fine and well balanced at the moment, so much so that one person can control huge areas whereas in reality several signallers would be required to control the same area. Professionalism mean nothing around a bunch of Amateur wannabees! Last edited: 01/04/2015 at 11:17 by mfcooper Reason: Fixed Formatting Log in to reply |
| Axle Counter Controls 01/04/2015 at 16:18 #70608 | |
GeoffM
6376 posts |
" said:" said:I was speaking to a CN track engineer last year about this and he said that very few breaks are detected by track circuits, something like the low 10s of percent. Breaks require a clean pull-apart which not all breaks are. Broken fishplates, as per the Metro North derailment, also go undetected because of the bonding around the joint.On the down side many people don't like them because they cannot detect a rail breaks (often but NOT always track circuits fail with a broken rail)...The reason why broken rails aren't always detected is because not all track circuits are double rail track circuits. Through S&C(point work) track circuits are single rail. If a rail breaks in a single rail track circuited area and it is on the non-track circuited rail, it will go undetected. Also some broken rails are not a clean break, some times part of the rail breaks away. " said: Places like North American use axle counters on many of their routes. Since axle counter detected sections are virtually limitless in length, they are ideal for low traffic areas such as freight only lines.Certainly not the US part of North America - they distrust them greatly and (wrongly) think track circuits always detect broken rails. According to the same bloke above, they need specific exemptions from the Good Book(s) because specifically track circuits are pretty much stated as a requirement, as opposed to "a method of detecting the absence of trains". SimSig Boss Log in to reply |
| Axle Counter Controls 01/04/2015 at 16:20 #70609 | |
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Muzer
718 posts |
I would suggest for now, adding a facility in the loader for sim developers to "flag" track circuits as actually being axle counters. I suspect this would potentially mean easier eventual implementation of axle counters for all sims that have this flag (admittedly though, with this tactic, the implementation would have to include no extra buttons etc. on the sim itself so it wouldn't be entirely prototypical — I'm more envisioning that the loader would perhaps mark axle counters differently in some way, and just have controls in the toolbar, menus, or right click to handle them).
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