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Post by wimblephil on Aug 28, 2015 4:45:43 GMT
Asking out of curiosity; what is it that causes the in-car automated announcements to run incorrectly and out of sync at times? (How do they work at all really!?)
The other morning I was on a D Stock that whilst coming into Fulham Broadway announced 'The next Station is West Brompton, change for London Overground and National Rail Services', upon arrival at FB it announced 'This is West Brompton...'. Between FB & West Brompton it announced 'The next station is Fulham Broadway, change for the Piccadilly line and District line services to other destinations' then at WB it corrected itself and played the usual 'This is West Brompton...' message. I found it interesting that it pieces the information together, for example I didn't think it would be possible to announce the Pic from FB!
I'm not sure where the out-of-sync-ness occurred, (headphones!) but I just noticed at FB.
Then whilst on a Circle line at Goldhawk Road, heading East it announced the next station as Hammersmith, but was correct by the next station.
This morning I was on the 05:11 from Wimbledon. As it pulled in and the doors opened, it announced the station as FB and proceeded to announce incorrectly until just before Putney Bridge, giving WB for Wimbledon Park, Earls Court for Southfields and High Street Kensington for East Putney where it announced it's termination!
It can confuse the hell out of the unfamiliar traveller, ...and even those who are regular!
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Post by norbitonflyer on Aug 28, 2015 6:56:59 GMT
The first two sound like the train knew where it was (GPS?) but thought it was travelling in the opposite direction. Possibly the driver had forgotten to reset the destination at turnround? The third one is stranger - it seems to have been counting stations ("dead reckoning" in nautical terms) but miscalculated its starting point.
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Post by fish7373 on Aug 28, 2015 19:24:10 GMT
The first two sound like the train knew where it was (GPS?) but thought it was travelling in the opposite direction. Possibly the driver had forgotten to reset the destination at turnround? The third one is stranger - it seems to have been counting stations ("dead reckoning" in nautical terms) but miscalculated its starting point. Hi works of the speedo FISH7373 |
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Post by Chris M on Aug 28, 2015 23:56:27 GMT
The first two sound like the train knew where it was (GPS?) but thought it was travelling in the opposite direction. Possibly the driver had forgotten to reset the destination at turnround? I once had this on a Class 350 from Birmingham to Liverpool which thought it was going from Liverpool to Birmingham. It got every station correct, but the next station was announced as the one previous. At least one woman missed her train as she dashed off upon hearing and believing the PA. |
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Post by norbitonflyer on Aug 29, 2015 0:13:53 GMT
The first two sound like the train knew where it was (GPS?) but thought it was travelling in the opposite direction. Possibly the driver had forgotten to reset the destination at turnround? I once had this on a Class 350 from Birmingham to Liverpool which thought it was going from Liverpool to Birmingham. It got every station correct, but the next station was announced as the one previous. At least one woman missed her train as she dashed off upon hearing and believing the PA. We often get this on the Waterloo - Waterloo roundabout services, which get confused on the Clapham Junction - Waterloo leg as to whether they are coming or going. They only call at Queenstown Road on the outward leg (anticlckwie) or inward (clockwise) , but the station often gets announced on the other leg as well So we get told to "mind the gap" there, when there are four tracks between you and the platform (and the train isn't stopping anyway) |
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Post by Chris M on Aug 29, 2015 0:18:55 GMT
to be fair, that is quite a gap.
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Post by t697 on Aug 29, 2015 18:15:46 GMT
The first two sound like the train knew where it was (GPS?) but thought it was travelling in the opposite direction. Possibly the driver had forgotten to reset the destination at turnround? The third one is stranger - it seems to have been counting stations ("dead reckoning" in nautical terms) but miscalculated its starting point. Well in the LUL fleets only D78 stock has GPS as part of the Customer Information System. It can work without that, the T/Op has to set the trip and the starting station while at the start station. GPS will set the starting position if it's got a GPS signal and the train is within about 150m of the station location. It's possible some D78 stock GPS don't work anymore I guess. Also if the trip has been set wrong it doesn't help! In the case where it became OK at West Brompton, maybe the GPS got a read to help that. Otherwise the D78 system relies on distance between each station to trigger the announcements If the doors open where it isn't expecting a station it gets confused. Not sure how you can get a Fulham Broadway announcement with the Earl's Court interchange info though! Perhaps it was in the middle of sorting itself out. The Circle at Goldhawk Road would be S stock which has no GPS. It reads the station ID from a beacon at each platform. This one sounds like the correct trip hadn't been set at Hammersmith and the T/Op corrected it on the journey. The 0511 from Wimbledon is empty stock on the way to Wimbledon. I see it was D78 stock that day (Trackernet!). Again possibly the CIS hadn't been set properly and if the GPS wasn't working, it might be several stations before the distances don't match the internal 'map' and stop the announcements. |
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Post by Tomcakes on Aug 29, 2015 22:19:36 GMT
There is an occasional issue on the Northern line where a train running southbound will think it's running northbound. Therefore at Highgate it will announce "This is Highgate, this train is for Barnet", on leaving highgate southbound it will announce "The next station is East Finchley" then on arrival at Archway will announce "This is Archway, this train is for Barnet" and so on and so forth. Presumably it is reset at each station but is just wrongly set direction-wise.
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Post by spsmiler on Aug 29, 2015 23:37:44 GMT
There is an occasional issue on the Northern line where a train running southbound will think it's running northbound. Therefore at Highgate it will announce "This is Highgate, this train is for Barnet", on leaving highgate southbound it will announce "The next station is East Finchley" then on arrival at Archway will announce "This is Archway, this train is for Barnet" and so on and so forth. Presumably it is reset at each station but is just wrongly set direction-wise. I was going to mention that as I've experienced it. Below is an image of a southbound train arriving at Brent Cross... that thinks its going to Edgware!  As for the cause, well maybe the computers which control these things have become sentient and reprogrammed themselves to operate as HAL.  Simon |
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Post by wimblephil on Sept 1, 2015 5:21:27 GMT
Not sure how you can get a Fulham Broadway announcement with the Earl's Court interchange info though! Perhaps it was in the middle of sorting itself out. This is what baffled me and got me questioning how it worked! Thanks for your detailed response. So only the D78 have GPS? Is there a reason it was deemed not required/wanted for the S-Stock? We often get this on the Waterloo - Waterloo roundabout services, which get confused on the Clapham Junction - Waterloo leg as to whether they are coming or going. They only call at Queenstown Road on the outward leg (anticlckwie) or inward (clockwise) , but the station often gets announced on the other leg as well So we get told to "mind the gap" there, when there are four tracks between you and the platform (and the train isn't stopping anyway) I've not experienced the Queenstown Road announcement on the non-Windsor lines myself, but on many occasion I have experienced the announcements to be out-of-sync by one station, possibly because of that pesky Queenstown Road! |
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Post by t697 on Sept 1, 2015 6:36:03 GMT
The D78 CIS supplier had GPS as a relatively standard feature. It does make the T/Op task a little easier setting up the trip when the GPS knows where the train is.
S stock was designed to have ATC which would know where the train is anyway, so no need for GPS. Even when the first ATC was cancelled, the interim CSDE system fitted includes station ID on the beacons, so again no need for GPS. GPS wouldn't help a whole lot on the core Circle line of course!
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Post by wimblephil on Sept 1, 2015 7:07:53 GMT
Well that all makes sense I suppose!
For the same reasons it wouldn't be particularly useful on the deep level lines I presume...!
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Post by Alight on Sept 2, 2015 17:27:36 GMT
I believe that most of the deep-level lines rely on transponders (or beacons) in the track, which is why the announcements are always triggered at set points. It took a while for the Jubilee line to receive these, hence the original system's inability to announce 'the next station' announcements until the early-mid '00s.
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Post by wimblephil on Sept 2, 2015 19:01:37 GMT
That's kind of how I thought it would work. I thought there was some sort of electronic code or signal or something transmitted at points on the track so that when the train passed over it, it would trigger the announcement. Evidently not!
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Post by t697 on Sept 2, 2015 21:12:57 GMT
That's kind of how I thought it would work. I thought there was some sort of electronic code or signal or something transmitted at points on the track so that when the train passed over it, it would trigger the announcement. Evidently not! Well the D stock system has no beacons at all and works fine even with the GPS turned off. The software has the station sequences etc programmed in. Although it is set to give the next station announcement 10 seconds after leaving the previous one, it is actually flexible enough to be set to give it at a specific distance from the previous station, which can be different for each station to station run just as with S stock. But when the D stock had its automated CIS fitted the LUL management fashion was for 10 seconds after the previous station, so that's what was set up. Changed their minds by the time of S stock... Generally the fleets without ATC need the automated CIS to be more self sufficient, as they don't have triggers from the wayside, ATC or otherwise. |
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Post by Alight on Sept 7, 2015 13:27:12 GMT
But when the D stock had its automated CIS fitted the LUL management fashion was for 10 seconds after the previous station, so that's what was set up. Changed their minds by the time of S stock... That's right and the Piccadilly line trains had their automated system setup around that time too, which similarly announces shortly after the train has departed. |
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Post by jimini on Sept 7, 2015 23:07:52 GMT
I might be completely making this up, but I'm sure I read somewhere (possibly even on here) that on the northern line "the next station is" announcements are triggered by some sort of wheel turn device on the train itself to judge the distance to the upcoming station, rather than a beacon on the track. Happy to be corrected as always!
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Post by superteacher on Sept 8, 2015 19:38:16 GMT
I might be completely making this up, but I'm sure I read somewhere (possibly even on here) that on the northern line "the next station is" announcements are triggered by some sort of wheel turn device on the train itself to judge the distance to the upcoming station, rather than a beacon on the track. Happy to be corrected as always! Heard something similar, but not sure if it was the Northern. |
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Post by Chris M on Sept 8, 2015 21:52:41 GMT
I've heard the same, but my recollection is of District line trains (C and/or D) rather than Northern line ones.
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Post by Alight on Sept 8, 2015 21:56:56 GMT
I think you could be right there RE: the Northern line as I remember reading something about it working it out through the deceleration as it approaches a station. Not quite sure the mechanics behind it as obviously the train can decelerate and come to a stand still before it's reached the next station, but it must be able to work it out.
Didn't the C Stock's system rely on wheel counts?
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Post by t697 on Sept 9, 2015 5:35:57 GMT
Northern line CIS has triggers from ATC that are distance related. So it is basically related to wheel rotation counts and signalling 'loops' for the approach message.
D78 District 'next station' is 10 seconds after the start of the run. Could have bee distance based but LU Corporate spec at the time was otherwise.
C stock was I seem to recall done on distance but with the distance set to be roughly equivalent to 10 seconds from the start of the run. For a few runs where the interstation distance is short, they were set to announce the next one immediately on wheel start from the prevous station.
S stock is the only one that (currently ;-))relies at all on trackside beacons that are not part of the signalling system and those are only at the stations. Everything else done off programmed distances etc.
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