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Post by Christopher J on May 11, 2005 23:16:14 GMT
Quite a technical(ish) question here. How do Train Describers, Dot Matrix Screens, ect 'know' what Train is coming next? Is there a sensor along the track which detects a certain type of Train and its destination as the Train passes over it and it's then shown on the describers and clears as the Train departs the station? Or is the Timetable installed into the Describers and it shows when necessary? Or am I wrong altogether? ;D An insight into how they work would be much appreciated.  Christopher. |
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Post by c5 on May 12, 2005 0:31:03 GMT
It depends what line you are on. The Northern and i think the (new bit?) of the Jubilee and the Piccadilly line have the Dot Matrix work off the train using a sysytem called PTI (Positive Train Identification) whereby the Train Operator types the trip/destination data in to the computer on the train and this passes on to the dot Matrix, the same destination will als be shown on the train. On lines like the Met, H&C, Circle and District,The Train Description (TD) is set up by the Signal Operator /SDM/SCCA as per the box sheets. The TD is then "carried along" with the train to the Dot Matrix at each station. However, sometimes there is not always the TD that you need. For example at Edgware Road, if you were to send a Train to Barking via the INNER rail, this would have to be put up as a Circle and changed once it reaches Gloucester Road, even though the train Operator is showing Barking on the front of the train  I hope this helps and I have not made it harder to understand ;D C5 |
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Post by Deleted on May 12, 2005 1:47:47 GMT
t/d is made up from a series of codes ABCDE each one or a combination of the code can be set as a t/d i.e
w/b
a = northfields
ab= richmond
e/b
a=upminster
ab=upminster depot
(btw these are not correct just for info)
on the district line the t/d is worked different from the dot matrix but at some places i.e embankment its connected to the t/d so the signalman can change a description. the t/d is sent from one station to another usually when the next track circuit after the station starter has dropped via a transmitter which sends a 50v d.c voltage to the next stations reciever and thus the process is carried along the line
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Post by citysig on May 12, 2005 8:10:02 GMT
Just to polish a bit of what C5 said. In the older manually operated systems, and the older control rooms, the description is passed along via the track circuits dropping. Normally the time until a train is due to arrive at the platform is forecast by the amount of distance still to travel. So track circuit A could be 1 minute's travelling time to the platform, so when a train reaches this, the dot matrix updates accordingly. However, when reaching areas such as the control area for Baker Street on the H&C, the following happens. The signal operator at Edgware Road ensures an eastbound train about to leave there has a correct train description, or changes it before the starter is cleared (C5, how many of your colleagues remember that from their training  ). The train leaves and then becomes seen by the computer. The computer allocates a train number to the description it detects and then routes the train accordingly. Train arrival times in the control area are calculated by the computer monitoring each train position in relation to each platform - rather than it's position on given track circuits. Just to confuse things, it does this by looking at which track circuits each train is on (the same as the older systems) but the difference is, it will (normally) check for any likely delay ahead and attempt to forecast the arrival time. After it's initial prediction, should a train take longer than expected to reach a certain point, or should we hold the service, the dot matrix displays change the prediction to "delay" until such times as it can accurately predict the arrival. We can change a train's description at any point in its journey through our area, and do not have to wait until it reaches a certain point. We also have a choice of every possible TD that may be needed on the line - however, not all of them actually display correctly on the platform. After passing through our area, the TD is then sent onward to whichever signal cabin or control room the train is next to visit. |
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Post by Deleted on Oct 25, 2005 16:34:28 GMT
the piccadilly does not use PTI well not between hyde park corner and acton town it uses the old system of transmitting a code down the line
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Post by Deleted on Oct 25, 2005 17:21:07 GMT
And the DMIs at Hyde Park Corner and Green Park refuse to play along when trains are reversed at the former - I was chatting with an Arnos Grove DMT who said that the DMIs displayed things like 'Not in Service' when a HPC T/D was put up at Earls Court.
Apparently all the other DMIs east of Green Park can display Hyde Park Corner or Green Park (I know the ones west of HPC can say the former too), but the ones at those two stations throw a wobbly...
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Post by Chris M on Oct 25, 2005 20:33:04 GMT
Who/what controls what the in-train display/announcements show?
Yesterday I got on a Mill Hill East train at Waterloo. All the platform describers and on train stuff agreed with this. Shortly after leaving Kentish Town the driver made an annoucnement that due to signalling problems the train would now be terminating at Archway.
The in train display continued to show MHE until we arrived at Tuffnel Park when it changed to display Archway and the auto-announcer agreed.
Shortly before arriving into Archway the driver made another announcement that the signalers had changed their mind and we were going to MHE again.
The display kept saying Archway though and when we arrived at Archway the announcer on the train and platform both said the train terminated here. The driver said "Not true - this train is heading north. This train is heading north, listen for an announcement at Finchley Central to find out where we are heading, but we're definately going NORTH from here".
All the way to East Finchely the in-train dot matrix was showing that the train was terminating at Archway.
At East Finchely the driver made an announcement that the train was now going to High Barnet and the display showed "High Barnet via Charing +" (which really added to the confusion of the poor Americans I was sat next to who were trying to get to MHE).
Finally when we got to Finchely Central everything did agree that the train was going to High Barnet. There was much confusion though about the train behind us - previously the driver had been saying that it was going to MHE (and indeed that is what the platform describers at Waterloo had said), however when we got to Finchely Central he basically said - there is a train behind us, it was going to be going to MHE but now I don't know. Look at the platform describers to find out wtf it is going - it was terminating at Finchley Central, and the one after that was going to High Barnet.
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Post by Deleted on Oct 25, 2005 21:41:29 GMT
However, sometimes there is not always the TD that you need. For example at Edgware Road, if you were to send a Train to Barking via the INNER rail, this would have to be put up as a Circle and changed once it reaches Gloucester Road, even though the train Operator is showing Barking on the front of the train On the District, Olympia is not available as a TD for trains coming through the city (i.e. from Tower Hill, Barking etc.) so they are shown as Putney Bridge all the way until Earls Court! |
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Post by Deleted on Oct 26, 2005 1:34:32 GMT
Regarding your query, Chris, if the 95 TMS is anything like it was on the 96s (and I'm led to believe that they're quite similar), then the driver should have been able to easily re-program the train destination into his TMS, which would then have corrected the auto-announcer and the passenger displays.
As I say, I'm not sure how the 95s differ from the 96s, but I'm sure the route setup will be similar.
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Post by Colin on Oct 26, 2005 4:11:50 GMT
Perhaps they are like the D stock refurbs (and the C's) in so far as the information can be reprogrammed any time - but will only change for the customers when the door open buttons are pressed. Hence you not seeing a change in information on the train till the next station. As far as the train op not knowing the destination - nice to know it's not just the District that has indecisive Line Controllers  ;D |
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Post by citysig on Oct 26, 2005 4:42:20 GMT
nice to know it's not just the District that has indecisive Line Controllers ;D Trust me, they are a new breed rapidly spreading to all parts. You only experience the indecision for your train. We experience it for any train. |
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Post by Colin on Oct 26, 2005 4:50:55 GMT
So you enjoy your job then ;D ;D |
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Post by q8 on Oct 26, 2005 6:00:34 GMT
Trust me, they are a new breed rapidly spreading to all parts. ----------------------------------------------------------------------- Are you saying that line controllers are 'uncontrollable'?  |
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Post by citysig on Oct 26, 2005 14:34:07 GMT
So you enjoy your job then ;D ;D I couldn't possibly comment further in such a public arena, so we'll just say it has it's moments Are you saying that line controllers are 'uncontrollable'? Again, I couldn't possibly comment further |
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Post by q8 on Oct 26, 2005 21:33:47 GMT
Citysig said his job has it's moments. He forgot to say that the best ones are at home.
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). The train leaves and then becomes seen by the computer. The computer allocates a train number to the description it detects and then routes the train accordingly.
;D
