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PTI
Mar 12, 2017 11:53:26 GMT
Post by dave1 on Mar 12, 2017 11:53:26 GMT
Doing some digging into Identra which had reset points but now trying to find out where the PTI was reset on the Northern any help appreciated.
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PTI
Mar 13, 2017 15:28:57 GMT
Post by Nortube on Mar 13, 2017 15:28:57 GMT
What is meant by the reset point? That's not something I've heard of before, unless it's a technical thing.
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PTI
Mar 13, 2017 18:10:39 GMT
Post by dave1 on Mar 13, 2017 18:10:39 GMT
What is meant by the reset point? That's not something I've heard of before, unless it's a technical thing. With Identra it was reset to the next destination and was normally the stop before terminating point. Was this the same on the Northern i.e. Colindale trains would reset at Hendon Central? and so on.
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PTI
Mar 14, 2017 6:05:01 GMT
Post by railtechnician on Mar 14, 2017 6:05:01 GMT
What is meant by the reset point? That's not something I've heard of before, unless it's a technical thing. With Identra it was reset to the next destination and was normally the stop before terminating point. Was this the same on the Northern i.e. Colindale trains would reset at Hendon Central? and so on. I'm not sure that it would make any sense to set a new destination (i.e. reset the PTI) before reaching the current one. AFAIAA Northern line PTI data contained more than the 'train' and 'service' info i.e. it also contained 'crew' info. That info would surely need to be collected on approach to the destination after leaving the previous station. Setting the PTI thumbwheels between stations makes little sense either, I would expect the driver of the new service to set the PTI thumbwheels prior to departure in much the same way that the signal operator would punch up the TD before clearing a train to depart from the terminal station. Apart from diverting PTI cables when Edgware was being remodelled in the 1990s I had nothing to do with it and have little more than a very scant appreciation of it although I see it as a system much like TD but with data collected at trackside transponders and forwarded rather than being sent ahead from station retransmission sites. You may or may not know that the Storno train radio on the tube lines had a limited form of PTI that was never used except by engineering staff chasing radio faults. That is to say that it was possible to positively discover the cab from which a train was being driven as well as the 'service' number by interrogating the train radio. The train (service) number would be returned followed by the cab number (actually the unique hard coded number of the train radio junction unit in that car). I am not sure if such was also applied to sub surface lines train radio, after all these years I simply cannot recall!
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PTI
Mar 14, 2017 9:36:01 GMT
Post by Nortube on Mar 14, 2017 9:36:01 GMT
The only way I can think of when a PTI resets is when the interrogator receives a new code and this would be set up by the driver at the last station before the terminus (e.g. Hendon). The new code being picked up by the interrogator as the train approached the terminus. See if this covers what you're asking about (it was current in 2006 / 2009) [ Click Here ]or here for the book page if the direct link doesn't work: [ Click Here ]Comments in the book re displaying the destination on the station Dot Matrix Indicators refer only to the PTI input. The actual DMI information depends on what it gets from the computer, the PTI being just one input. The booked timetable (or whatever) may be another input - hence a terminus such as Edgware can show the destination of a train when that reversing train may still be a few stations away.
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PTI
Mar 14, 2017 10:32:48 GMT
Post by dave1 on Mar 14, 2017 10:32:48 GMT
With Identra it was reset to the next destination and was normally the stop before terminating point. Was this the same on the Northern i.e. Colindale trains would reset at Hendon Central? and so on. I'm not sure that it would make any sense to set a new destination (i.e. reset the PTI) before reaching the current one. AFAIAA Northern line PTI data contained more than the 'train' and 'service' info i.e. it also contained 'crew' info. That info would surely need to be collected on approach to the destination after leaving the previous station. Setting the PTI thumbwheels between stations makes little sense either, I would expect the driver of the new service to set the PTI thumbwheels prior to departure in much the same way that the signal operator would punch up the TD before clearing a train to depart from the terminal station. Apart from diverting PTI cables when Edgware was being remodelled in the 1990s I had nothing to do with it and have little more than a very scant appreciation of it although I see it as a system much like TD but with data collected at trackside transponders and forwarded rather than being sent ahead from station retransmission sites. You may or may not know that the Storno train radio on the tube lines had a limited form of PTI that was never used except by engineering staff chasing radio faults. That is to say that it was possible to positively discover the cab from which a train was being driven as well as the 'service' number by interrogating the train radio. The train (service) number would be returned followed by the cab number (actually the unique hard coded number of the train radio junction unit in that car). I am not sure if such was also applied to sub surface lines train radio, after all these years I simply cannot recall! RT thanks for the info on Storno I suppose thinking about it all bits of equipment have a number and if they are recorded then it should be able to identify which train has them. I was thinking along the lines that on the Vic line they set the identra to the next destination at the station before they terminate so would the same apply to the Northern line and it would only be the thumbwheels for the destination and if there were a change of T/Op then the new one would change at the other end.
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PTI
Mar 14, 2017 10:40:39 GMT
Post by dave1 on Mar 14, 2017 10:40:39 GMT
The only way I can think of when a PTI resets is when the interrogator receives a new code and this would be set up by the driver at the last station before the terminus (e.g. Hendon). The new code being picked up by the interrogator as the train approached the terminus. See if this covers what you're asking about (it was current in 2006 / 2009) [ Click Here ]or here for the book page if the direct link doesn't work: [ Click Here ]Comments in the book re displaying the destination on the station Dot Matrix Indicators refer only to the PTI input. The actual DMI information depends on what it gets from the computer, the PTI being just one input. The booked timetable (or whatever) may be another input - hence a terminus such as Edgware can show the destination of a train when that reversing train may still be a few stations away. Nortube thanks see my reply to RT about the Vic line. I have looked through the book and on page 8 it mentions about changing of the destination at Stockwell but nothing would be seen until the Oval due to the location of the interrogator now would there have been one of these before the terminal point? I have found a photo on BowRoad's flicker site you can see the sign about PTI reset point, I love the sign which says Danger Tunnel mouth. Here
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PTI
Mar 14, 2017 15:57:49 GMT
Post by railtechnician on Mar 14, 2017 15:57:49 GMT
The only way I can think of when a PTI resets is when the interrogator receives a new code and this would be set up by the driver at the last station before the terminus (e.g. Hendon). The new code being picked up by the interrogator as the train approached the terminus. See if this covers what you're asking about (it was current in 2006 / 2009) [ Click Here ]or here for the book page if the direct link doesn't work: [ Click Here ]Comments in the book re displaying the destination on the station Dot Matrix Indicators refer only to the PTI input. The actual DMI information depends on what it gets from the computer, the PTI being just one input. The booked timetable (or whatever) may be another input - hence a terminus such as Edgware can show the destination of a train when that reversing train may still be a few stations away. The first link gives a 403 Forbidden error but the second one is ok. I see no mention of 'crew' data in the PTI notes, however, I am sure that the original 1970s PTI specification made provision for such in its data string. What seems odd to me is the concept of changing the PTI thumbwheels before arriving at the destination, I am thinking of a train on its last timetabled run which I might reasonably expect to cause to be put up a 'stops here' TD at the terminus arrival platform. No doubt the PTI data would also carry a route to the depot or sidings so there would be no further data to forward. A reset would therefore presumably lead to the mentioned noughts and crosses scenario. However, as I said I had nothing to do with Northern line PTI so I am not au fait with the details of its operation.
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PTI
Mar 14, 2017 16:58:03 GMT
Post by dave1 on Mar 14, 2017 16:58:03 GMT
The only way I can think of when a PTI resets is when the interrogator receives a new code and this would be set up by the driver at the last station before the terminus (e.g. Hendon). The new code being picked up by the interrogator as the train approached the terminus. See if this covers what you're asking about (it was current in 2006 / 2009) [ Click Here ]or here for the book page if the direct link doesn't work: [ Click Here ]Comments in the book re displaying the destination on the station Dot Matrix Indicators refer only to the PTI input. The actual DMI information depends on what it gets from the computer, the PTI being just one input. The booked timetable (or whatever) may be another input - hence a terminus such as Edgware can show the destination of a train when that reversing train may still be a few stations away. The first link gives a 403 Forbidden error but the second one is ok. I see no mention of 'crew' data in the PTI notes, however, I am sure that the original 1970s PTI specification made provision for such in its data string. What seems odd to me is the concept of changing the PTI thumbwheels before arriving at the destination, I am thinking of a train on its last timetabled run which I might reasonably expect to cause to be put up a 'stops here' TD at the terminus arrival platform. No doubt the PTI data would also carry a route to the depot or sidings so there would be no further data to forward. A reset would therefore presumably lead to the mentioned noughts and crosses scenario. However, as I said I had nothing to do with Northern line PTI so I am not au fait with the details of its operation. That first link was the same for me I am sure there was a wheel for crew details as well. I think I have got my head around this and it goes like this. Train going to Edgware does nothing at Hendon Central and when the train approached Colindale its destination is read and the required route is set and when it gets to Burnt Oak then the T/Op would set up the code for the next SB trip, a train which is going to reverse at Colindale sets up the code for the next SB trip at Hendon Central. And lastly a train that is not going to go anywhere else after reaching Edgware would not have to do anything as it would have had a code for Edgware depot already set up.
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PTI
Mar 14, 2017 20:51:55 GMT
Post by Nortube on Mar 14, 2017 20:51:55 GMT
I sent somebody a direct link to a diagram a couple of weeks ago and they got the same error message. I tried the same link and one time it worked, the second time it didn't. I've not experimented further, but I suspect that it may possibly be due to an upgrade that my host did the other week, although I'm not sure how it would only affect downloads.
I think it also depends on the browser. I'm having the same problem in Firefox, but it seems to work in Pale Moon.
I'll have to look into it when I get time and remember it.
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PTI
Mar 14, 2017 21:18:41 GMT
Post by Nortube on Mar 14, 2017 21:18:41 GMT
> I love the sign which says Danger Tunnel mouth. I don't see the point of having that sign there, unless there's a secret tunnel on the other side of the IMR door and there certainly wasn't one when I was last inside there It would possibly make a bit more sense if it was on the wall at the tunnel entrance / exit, but it would really be stating the "bleedin' obvious"! Many years ago (early nineties I think) a Guard was killed in the NB tunnel some distance from the Hendon entrance. From what I remember There were some passengers in the rear car, but they didn't do anything until the train go to Colindale and the doors didn't open. The Guard's door was open and it was assumed that he fell into the tunnel from the open door. I think one opinion was that he may have been waving to the Guard on the train on the SB platform and was thus late in closing his door.
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PTI
Mar 14, 2017 21:32:08 GMT
Post by Nortube on Mar 14, 2017 21:32:08 GMT
The PTI interrogator approaching a terminus was normally close to the first set of points (facing or trailing) that a train would pass over. Because the interrogators were on the right-hand side of the four foot in the direction of travel (i.e. on the drivers’ off-side, with the on-train transmitter directly above the interrogator as the train passed over it), separate interrogators had to be used
Departing a terminus, the interrogator was usually just after the last set of points that any train departing the terminus would pass over. At Edgware, they were positioned south of 7B points (the final crossover south of the station)
For a departing train, having the interrogator as close as possible to the last points meant that the destination of the train could be picked up at the earliest opportunity.
For an arriving train, in theory, it wouldn’t matter where the interrogator was sited between the last station and the terminus. However the closer it was to the terminus, the less cable would be required from the interrogator to the IMR or wherever it terminated within the station area.
I’ve used the past tense in the description, as that’s how it worked at 2009. It probably still works the same today.
Although there was a third set of rotary switches so that a crew number could be set up, these were rarely used by anybody (myself included) as I don’t think that at the time the crew number information was used. When 95 stock was introduced, crew number details were entered as well as the train number and destination. A crew number is associated with a train number, but I don’t know if that is from information taken from the PTI or the duty sheets. Knowing the crew number can be an advantage when the job goes up the wall and reformations are taking place and there is more than one train with the same train number running around. I also assume that it would be easy for a computer to have the potential to be able to flag up when a driver might be late for Meal Relief, over their hours etc. if required.
Dave1 – your comments about the setting of the PTI and the train going to depot not needing a reset are correct. The depot code was normally one digit higher than the terminus reversing code – e.g. Edgware via CX 021. Edgware via CX then to depot at Edgware 022.
Trains stabling at High Barnet would have the PTI set as 002, 012 or 042. However the driver would still have to operate the keyswitch at the north end of that train’s platform to tell the equipment that the train was for depot. Failure to do so within a set time of the train stopping could mean that the starter could clear for a SB move unless the regulator noticed and overrode it. Or, more commonly, nothing happened and the shunt wouldn’t clear for depot unless the regulator manually cleared it. Nothing worse than to have tipped out and changed ends then get onto the controller to find out why the shunt hasn’t cleared yet, only to be told to go back and operate the switch!
All numbers associated with the PTI are Binary Coded Decimal, therefore the numbers 8 and 9 are never used. Northern line train numbers were BCD when I started in 1973 and I suspect this system came into place when programme machines took over (using an 8 or 9 would mean an extra hole / wire). The duty (crew) numbers were normal decimal (e.g. Morden had duties 107, 109, 109, 110 etc. I suspect that these changed to BCD with the introduction of the PTI on the line.
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PTI
Mar 14, 2017 23:37:44 GMT
Post by railtechnician on Mar 14, 2017 23:37:44 GMT
I sent somebody a direct link to a diagram a couple of weeks ago and they got the same error message. I tried the same link and one time it worked, the second time it didn't. I've not experimented further, but I suspect that it may possibly be due to an upgrade that my host did the other week, although I'm not sure how it would only affect downloads. I think it also depends on the browser. I'm having the same problem in Firefox, but it seems to work in Pale Moon. I'll have to look into it when I get time and remember it. FWIW I use Google chrome to view LTF, I reserve firefox for such things as online banking which will no longer work in Chrome. I dislike Microsoft Edge and Internet Explorer as they have their own limitations but I do also use Opera on this particular PC. I use Safari on several of my other PCs but no browser seems fit for all eventualities. Pale Moon I have not heard of !
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PTI
Mar 14, 2017 23:45:10 GMT
Post by railtechnician on Mar 14, 2017 23:45:10 GMT
> I love the sign which says Danger Tunnel mouth. I don't see the point of having that sign there, unless there's a secret tunnel on the other side of the IMR door and there certainly wasn't one when I was last inside there It would possibly make a bit more sense if it was on the wall at the tunnel entrance / exit, but it would really be stating the "bleedin' obvious"! Many years ago (early nineties I think) a Guard was killed in the NB tunnel some distance from the Hendon entrance. From what I remember There were some passengers in the rear car, but they didn't do anything until the train go to Colindale and the doors didn't open. The Guard's door was open and it was assumed that he fell into the tunnel from the open door. I think one opinion was that he may have been waving to the Guard on the train on the SB platform and was thus late in closing his door. I agree that the danger tunnel mouth sign is superfluous where it is mounted, perhaps it should be on a post on approach to the tunnel mouth, after all if mounted at the tunnel mouth it wouldn't be any kind of warning at all. It was certainly not unknown for guards to be late closing their doors, ISTR an event in the 1970s where a guard looked rearward with his head out the door as the train accelerated away from a tube platform. The headwall decapitated him as I recall although I can't recall which line it was on.
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PTI
Mar 15, 2017 0:08:21 GMT
Post by railtechnician on Mar 15, 2017 0:08:21 GMT
Nortube Numbers 8 and 9 did not exist on any line, although called binary coded decimal what was actually used was octal i.e. all the train timetables were written in octal (when programme machines were first invented octal was state of the art for the computers of the time) and so all the train numbers are octal. On the P/Mc roll the 'BCD' numbering bits were 2,1 ; 4,2,1 ; 4,2,1 thus the highest possible train number was 377. However, the actual highest train number was 374 because the first number on the roll was 375 for start of service and the last number on the roll was 376 for end of service. Signal staff used 377 i.e. 11;111;111 to check that all the fingers were working correctly for train numbers when investigating P/Mc faults. I don't know about crew duty numbers but I expect that they would have been converted to octal from decimal one way or another.
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