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Post by Deleted on Jul 13, 2021 17:25:25 GMT
Does anyone know why on some of the DMIs the 'next train' list empty, but just as the train approaches, it will come up with the next train?
Not like this on any other lines I don't think.
<<Rincew1nd: thread title changed from "DMI">>
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Post by Deleted on Jul 13, 2021 18:13:49 GMT
Have you got a particular station in mind? As some systems on different parts on different lines work completely different
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Post by MoreToJack on Jul 13, 2021 19:33:55 GMT
DMI = Dot Matrix Indicator - this appears to relate to station-mounted screens so is more properly called a Train Describer.
Just a reminder to everyone to expand any initialisms on first use for those who may not be aware of them.
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Post by goldenarrow on Jul 13, 2021 20:13:35 GMT
The scenario you describe tends to happen where a station is fringing with another area of signalling control especially if it’s a legacy system which can often inhibit more advanced information being shown apart from what is immediately “offered up”.
South Harrow (eastbound) springs to mind as that’s where Rayners Lane signal cabin which I believe runs a novel radio based train description system gives over to Piccadilly Interim Control Upgrade (PICU) systems. It’s been a while since I’ve used the station but you used to only get train information once the train had “dropped on” to the PICU area of control which begins somewhere near Roxeth Viaduct.
Same goes for Hillingdon (eastbound) which only shows information once a train has left Uxbridge and that information is stringed to all stations westward to West Harrow where Rayners Lane signal cabin hands over to Harrow signal cabin which again runs off a different system.
I don’t know what the east end of the District is running Train Describer (TD) wise but I imagine it’s another isolated legacy system with limited capabilities.
One of the benefits for Four Lines Modernisation is that these non-standard systems are being phased out and replaced with a unified one. Already in areas where Communications Based Train Control (CBTC) has gone live we’ve seen the infamous TD gaps between Goldhawk Road and Paddington (suburban) eliminated and terminus station platforms like Aldgate are displaying countdown information for trains that have yet to depart or yet to arrive as well.
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Tom
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Post by Tom on Jul 13, 2021 21:12:50 GMT
South Harrow (eastbound) springs to mind as that’s where Rayners Lane signal cabin which I believe runs a novel radio based train description system gives over to Piccadilly Interim Control Upgrade (PICU) systems. It’s been a while since I’ve used the station but you used to only get train information once the train had “dropped on” to the PICU area of control which begins somewhere near Roxeth Viaduct. Not quite. There's very little train description circuitry at Rayners Lane - you can set up a description at Ruislip Siding, but there are only four descriptions available going EB (Picc, Picc Special, Met, Met Special) and similarly only four WB (Ruislip, Uxbridge, Uxbridge Sidings and Special). None of these drive any platform signs between Rayners Lane and Ruislip - they are purely for driving the signaller's indications. Leaving Rayners Lane going East, the incoming description from Ruislip again only drives the signaller's display. The signaller needs to set up a new description for Picc trains, but has no setup facility for Met trains (this is done by the Harrow signaller). For an departing Picc train, the description isn't sent to South Harrow until the train departs from Rayners Lane, so little over two minutes away. All the platform signs on the Uxbridge Branch are run off a Station Management System installed when the Dot Matrix signs were provided as part of Metronet's station refurbishment programme - I'm not sure where they get their data from! |
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Post by Deleted on Jul 13, 2021 21:34:21 GMT
East end of the District is indeed still working a legacy style TD system with the traditional ABCDE codes. These do feed into CBTC at various locations Bow Road and South Kensington currently but as CBTC progresses this will change of course. The west end of the District South Kensington to West Kensington / Putney Bridge / High Street Kensington still uses the ABCDE codes. At West Kensington PICU takes over to Ealing Broadway, not sure how the Richmond line works as its NR (Network Rail) signalling though.
Most of the DMI's are fed these days from Trackernet on the District and not through the actual equipment on site any longer which used to feed the older style of DMI's
Due to problems with the District today all South Kensington reversers were showing up at Sloane Square on the EB (Eastbound) as Circle's and once the signaller at HSCC (Hammersmith Service Control Centre also known as Grove Road done at Edit to the train and assign it a train number and destination, this then gave the system all the info it required to route the train correctly. This was certainly happening around 09:30 when I was watching it this was causing a 1 to 2min delay on every train at Sloane Square when the train was reversing WB (Westbound) to EB at South Kensington
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Post by d7666 on Jul 14, 2021 13:25:20 GMT
DMI = Dot Matrix Indicator - this appears to relate to station-mounted screens so is more properly called a Train Describer. Just a reminder to everyone to expand any initialisms on first use for those who may not be aware of them.I'm a bit puzzled by this if referring to station screens that passengers see, which I think the OP question is about. The actual device mounted in station platforms is correctly called a DMI (dot matrix indicator) by all of us in that asset area responsible for them. A DMI displays more than TD data : the DMI display "next train" minutes and the 24 h clock, etc, these do not come from TD, nor do the messages such as "train approaching" and so on. The whole lot makes it a DMI. I do know the terms DMI get muddled with VEID and THID (Visual Electronic Information Display, which in simple terms is a platform DMI, and Ticket Hall Information Display, which are the large TV-type summary screens, mostly found in, obviously, the ticket halls etc). |
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Post by MoreToJack on Jul 14, 2021 16:14:23 GMT
Whilst a particular asset area may refer to something in a certain way, other asset areas may also refer to things in the same way.
DMI simply means dot matrix indicator to the majority of people. DMIs are also on trains and in numerous other areas.
A train describer is literally the thing that describes the train.
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Post by Deleted on Jul 14, 2021 18:21:49 GMT
DMI = Dot Matrix Indicator - this appears to relate to station-mounted screens so is more properly called a Train Describer. Just a reminder to everyone to expand any initialisms on first use for those who may not be aware of them.I'm a bit puzzled by this if referring to station screens that passengers see, which I think the OP question is about. The actual device mounted in station platforms is correctly called a DMI (dot matrix indicator) by all of us in that asset area responsible for them. A DMI displays more than TD data : the DMI display "next train" minutes and the 24 h clock, etc, these do not come from TD, nor do the messages such as "train approaching" and so on. The whole lot makes it a DMI. I do know the terms DMI get muddled with VEID and THID (Visual Electronic Information Display, which in simple terms is a platform DMI, and Ticket Hall Information Display, which are the large TV-type summary screens, mostly found in, obviously, the ticket halls etc). Where you think it gets the data from |
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Post by d7666 on Jul 15, 2021 16:38:10 GMT
I'm a bit puzzled by this if referring to station screens that passengers see, which I think the OP question is about. The actual device mounted in station platforms is correctly called a DMI (dot matrix indicator) by all of us in that asset area responsible for them. A DMI displays more than TD data : the DMI display "next train" minutes and the 24 h clock, etc, these do not come from TD, nor do the messages such as "train approaching" and so on. The whole lot makes it a DMI. I do know the terms DMI get muddled with VEID and THID (Visual Electronic Information Display, which in simple terms is a platform DMI, and Ticket Hall Information Display, which are the large TV-type summary screens, mostly found in, obviously, the ticket halls etc). Where you think it gets the data from w.r.t. passenger information - which is the subject here - TD is but one input system. DMI is an output device. The thing on the platform has other inputs not from TD - e.g. the 24 h clock, and other text messages. That's why that thing on the platform - which is what the OP is refering to - is a DMI not a TD. Or, bouncing it back, where do you think the 24 clock comes from ? or the other text messages ? I'd be pretty sure lottery results or whatever info like that is or was put out on DMI has not come from TD. |
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Post by class411 on Jul 15, 2021 17:35:34 GMT
Where you think it gets the data from w.r.t. passenger information - which is the subject here - TD is but one input system. DMI is an output device. The thing on the platform has other inputs not from TD - e.g. the 24 h clock, and other text messages. That's why that thing on the platform - which is what the OP is referring to - is a DMI not a TD. Or, bouncing it back, where do you think the 24 clock comes from ? or the other text messages ? I'd be pretty sure lottery results or whatever info like that is or was put out on DMI has not come from TD. Does the platform DMI take inputs from several sources and display them according to a priority system, of does it have lines (or blocks of lines) dedicated to each source? |
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Post by zbang on Jul 15, 2021 19:44:56 GMT
If we're going to get pedantic here, the display (be it dot-matrix, video, or what) shows what the controller sends to it. The controller might get data from various sources and select/format what's needed for an individual display. So a DMI (dot matrix indicator) can be used as a TD (train describer) but only if something is sending it train info. (Or, consider the system, not just the devices.)
Who makes most of the dot-matrix displays used by TfL in stations? Daktronics is very common in the US, but I'm not sure how much presence they have in the UK (although there is an office in Bristol).
ABCDE codes?
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Tom
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Post by Tom on Jul 15, 2021 19:53:15 GMT
Does the platform DMI take inputs from several sources and display them according to a priority system, of does it have lines (or blocks of lines) dedicated to each source? The modern ones do, yes. There is normally a fixed area for the clock, but the rest can vary between train information, service messages etc. The original Thorn and GEC signs could sometimes display different inputs depending on their configuration - but in their most basic (known as stand-alone) they only gave train information. In this case (as the OP asked) they only receive information when it is available which, if close to a junction, may not be until an approaching train has passed the junction. Have a look here, as written by the late Mike Horne. |
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rincew1nd
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Post by rincew1nd on Jul 15, 2021 20:03:48 GMT
I've changed the thread title to a generic term (which is not up for debate). It would be nice if we could answer the question in the OP before diving off into the technicalities of how these various data are processed/presented.
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Post by Deleted on Jul 15, 2021 20:49:29 GMT
Does the platform DMI take inputs from several sources and display them according to a priority system, of does it have lines (or blocks of lines) dedicated to each source? The modern ones do, yes. There is normally a fixed area for the clock, but the rest can vary between train information, service messages etc. The original Thorn and GEC signs could sometimes display different inputs depending on their configuration - but in their most basic (known as stand-alone) they only gave train information. In this case (as the OP asked) they only receive information when it is available which, if close to a junction, may not be until an approaching train has passed the junction. Have a look here, as written by the late Mike Horne. Lovely programme machines  |
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Post by Chris L on Jul 16, 2021 7:35:39 GMT
If we're going to get pedantic here, the display (be it dot-matrix, video, or what) shows what the controller sends to it. The controller might get data from various sources and select/format what's needed for an individual display. So a DMI (dot matrix indicator) can be used as a TD (train describer) but only if something is sending it train info. (Or, consider the system, not just the devices.) Who makes most of the dot-matrix displays used by TfL in stations? Daktronics is very common in the US, but I'm not sure how much presence they have in the UK (although there is an office in Bristol). ABCDE codes? Daktronics bought out Data Display Limited an Irish company who used to supply dot matrix signs. This seems to have expanded the range of display types into the modern age. |
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Post by eastlondoner123 on Jul 17, 2021 21:45:26 GMT
The only good DMI on these 4 lines is Westminister as that was a Tube Lines Managed station so has a proper DMI set up that also includes the announcement, every destination can we shown on that, the other day when the line had issues, I saw West Kensington, Olypia, Parsons Green, all with announcements too.
Bromley By Bow and Bow Road and comple other stations have Metronet style DMI but no announcements, Gloucester Road has few announcements with there DMI, Farringdon used to but been switched off and not put back on, emailed TFL loads of times about this.
Whos in charge of all these DMIs at stations as I said the lady doing her station safety patrol checks at Covent Garden yesterday why are the announcements for the DMI not working, she goes she does not know how they are worked, also the ones at Acton Town don't seem to play either nor Hounslow East, Osterley, Hounslow Central, Hounslow West.
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Post by eastlondoner123 on Jul 17, 2021 22:28:53 GMT
Alot of these new mini smaller DMIs are meant to have working announcements either, the ones installed at Victoria do, guess they not be switched on at other stations.
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