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Post by railtechnician on Apr 27, 2015 21:56:18 GMT
With respect to special floodgate telephones on the Moorgate - London Bridge section they were fitted as follows.
Moorgate N/B H/W -- Z39 Moorgate S/B H/W -- Z40 Bank N/B H/W -- Z39 Bank S/B -- none London Bridge -- none
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Post by hellocontrol on Apr 28, 2015 10:06:26 GMT
I found these scans up earlier. I'd probably originally photocopied them in from the bound Traffic Circular archive that used to exist at Broadway, hence the cut-off at the binding side. The first one - TC 21 1940 - mentions higher speed restrictions off-peak, including Bank - London Bridge SB. Unfortunately, it refers to an earlier paragraph on the previous page (which I don't have). I did wonder if this would have been a switched-in restriction that only illuminated off-peak. However, on reflection, I decided that this has nothing to to with the speed restriction which was originally mentioned at the start of this thread because: 1. The 25mph speed restriction that the TC refers to would be the one that starts from Bank SB starter 2. It would have meant a lot of extra work and expense to enforce the higher speed restriction with speed signalling when there was no need to do so. I assume that it was just up to the drivers to think "it's off-peak, I'd better go 5mph less on this bend" ! I've posted the page out of interest though. As the floodgates at London Bridge were mentioned, I've also added the exert from a 1940's TC (possibly no.18) regarding the through running between Moorgate and London Bridge after the installation of the floodgates. In fact, as I'm typing this message and reading the TC entry, it actually mentions the speed restriction sign itself and its purpose, and it's not your normal speed restriction sign! If anybody has a clearer scan of this traffic circular entry (and perhaps the missing page of TC21 that contains paragraph 21, perhaps they could post it or message me. Click on the photos below to enlargeIt seems that the trains speed was indicated on the indicator a bit like those modern day ones you see when driving on the road.
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Post by hellocontrol on Apr 28, 2015 10:09:04 GMT
With respect to special floodgate telephones on the Moorgate - London Bridge section they were fitted as follows. Moorgate N/B H/W -- Z39 Moorgate S/B H/W -- Z40 Bank N/B H/W -- Z39 Bank S/B -- none London Bridge -- none RT where you have put the Z in front of the number IIRC Z indicates something special?
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Post by Nortube on Apr 28, 2015 10:13:20 GMT
Early radar?
From the Traffic Circular description and looking at the posted diagram in this thread, it would appear that no signals in this area are speed controlled. All that happens is that the speed indicator circuit is turned on / off by the occupation of a track circuit. This may be an example of what Rules and Regs used to teach as an 'Auxiliary track circuit' - a track circuit that was also used for other purposes as well as controlling a signal.
Looking at the diagram, it would seem that the only part of the speed indicator circuit that is shown are the track relay contacts for track circuits 637a and 637a. The main circuitry for detecting and displaying the speed is not shown on the diagram and would be on diagram / sheet AS11949/12.
If I'm following it correctly: When the first pair of wheels passes the blockjoint at FNX6371, track circuit 637a drops (the track is 'occupied') and this, amongst other things, closes contacts 7 and 12 on 637A track relay (637A TR), effectively closing two switches on the speed indicator circuit. The end result is that the train's speed will be displayed on the speed restriction sign.
When the first pair of wheels passes the blockjoint at RFNX637, track circuit 637b drops and this, amongst other things, closes contacts 1, 2, and 5 on 637B track relay (637B TR), effectively closing a further three switches on the speed indicator circuit.
After the last pair of wheels cleared FNX639, and thus track circuits 637a and 637b were back up (unoccupied), the speed indicator circuit would turn off.
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Post by hellocontrol on Apr 28, 2015 10:14:09 GMT
hellocontrol, I believe most of the relays in a floodgate relay room are UP i.e. in the energised position as that is the normal condition for the vast majority of signal relays except for the delta relays which as I mentioned are normally DOWN and pickup with the passage of every train. Remember that I also mentioned up thread that floodgate relays are in the selections of the signals, these would normally be up unless the floodgate is closed, closing or about to close. It is difficult to be specific without a set of drawings but do note that the few shown on the strip print are all normally energised. The floodgate relay rooms are not hazardous per se although they are quite unhealthy to linger in as they are very hot because of their tight confines and all the permanently energised relays acting like a heating system. Perhaps the worst I have been in was the first I ever worked in back in the late 1970s deep down in the bowels of Kennington station and little bigger than a toilet cubicle having a single relay rack and a rather browned track diagram due to the overheating. The humidity was also extremely high and the environment one of the most uncomfortable to work in, something akin to working in the tropics although I have no personal experience of that. There are many such nooks and crannies all over the system but especially in the oldest places. RT I meant some of the relays that are only associated with the floodgates would have remained in the same position since the floodgates were last tested. Many years ago I went into one of these rooms and I am sure there was also another room which could not be accessed but looking through the window of the door it appeared as some sort of electrical equipment and I was already with the floodgate equipment.
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Post by railtechnician on Apr 28, 2015 11:39:27 GMT
With respect to special floodgate telephones on the Moorgate - London Bridge section they were fitted as follows. Moorgate N/B H/W -- Z39 Moorgate S/B H/W -- Z40 Bank N/B H/W -- Z39 Bank S/B -- none London Bridge -- none RT where you have put the Z in front of the number IIRC Z indicates something special? Yes Z means special and the number indicates which floodgate the telephone is associated with.
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Post by railtechnician on Apr 28, 2015 12:21:26 GMT
Early radar? From the Traffic Circular description and looking at the posted diagram in this thread, it would appear that no signals in this area are speed controlled. All that happens is that the speed indicator circuit is turned on / off by the occupation of a track circuit. This may be an example of what Rules and Regs used to teach as an 'Auxiliary track circuit' - a track circuit that was also used for other purposes as well as controlling a signal. Looking at the diagram, it would seem that the only part of the speed indicator circuit that is shown are the track relay contacts for track circuits 637a and 637a. The main circuitry for detecting and displaying the speed is not shown on the diagram and would be on diagram / sheet AS11949/12. If I'm following it correctly: When the first pair of wheels passes the blockjoint at FNX6371, track circuit 637a drops (the track is 'occupied') and this, amongst other things, closes contacts 7 and 12 on 637A track relay (637A TR), effectively closing two switches on the speed indicator circuit. The end result is that the train's speed will be displayed on the speed restriction sign. When the first pair of wheels passes the blockjoint at RFNX637, track circuit 637b drops and this, amongst other things, closes contacts 1, 2, and 5 on 637B track relay (637B TR), effectively closing a further three switches on the speed indicator circuit. After the last pair of wheels cleared FNX639, and thus track circuits 637a and 637b were back up (unoccupied), the speed indicator circuit would turn off. Not quite correct! 637 ATR 7&12 back contacts are normally open whereas 637 BTR front contacts 1,2&5 are normally closed when the tracks are unoccupied. When a train drops onto 637 A track, 637 ATR 7&12 back contacts make and when the train then drops onto 637 B track 637 BTR front contacts 1,2&5 break. As the train proceeds 637 ATR picks up once again breaking back contacts 7&12 followed by 637 BTR picking up making front contacts 1,2&5 again. It is true that there is no speed controlled signalling here but 637 A and 637 B tracks form a timing section i.e. a train will take a finite time to traverse the two tracks, e.g. the time taken from 637 ATR dropping to 637 BTR picking up as the train proceeds or alternatively from 637 ATR dropping to 637 BTR dropping. We cannot know precisely what forms the timing section without either the scale plan or the bookwiring but typically as the train proceeds over the timing section a time relay will be started and wound up to determine whether the required speed is being exceeded or not. Indeed I cannot speculate upon the circuitry further but would suggest that the output displayed on the sign would be very basic and not too accurate unless the actual speed was below or close the specification. Your definition of 'Auxilliary Track Circuit' might apply to virtually every track circuit on the system as track circuits drive train describers, auto announcers, MTG lighting etc. I think perhaps the term would more correctly be 'Track Relay Auxilliary Circuit' and that is a term that I ceased to hear decades ago. However, I would not be surprised to learn that your term is what was taught on the Operating side where function rather than circuitry was the most important knowledge to acquire.
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Post by railtechnician on Apr 28, 2015 12:33:23 GMT
hellocontrol, I believe most of the relays in a floodgate relay room are UP i.e. in the energised position as that is the normal condition for the vast majority of signal relays except for the delta relays which as I mentioned are normally DOWN and pickup with the passage of every train. Remember that I also mentioned up thread that floodgate relays are in the selections of the signals, these would normally be up unless the floodgate is closed, closing or about to close. It is difficult to be specific without a set of drawings but do note that the few shown on the strip print are all normally energised. The floodgate relay rooms are not hazardous per se although they are quite unhealthy to linger in as they are very hot because of their tight confines and all the permanently energised relays acting like a heating system. Perhaps the worst I have been in was the first I ever worked in back in the late 1970s deep down in the bowels of Kennington station and little bigger than a toilet cubicle having a single relay rack and a rather browned track diagram due to the overheating. The humidity was also extremely high and the environment one of the most uncomfortable to work in, something akin to working in the tropics although I have no personal experience of that. There are many such nooks and crannies all over the system but especially in the oldest places. RT I meant some of the relays that are only associated with the floodgates would have remained in the same position since the floodgates were last tested. Many years ago I went into one of these rooms and I am sure there was also another room which could not be accessed but looking through the window of the door it appeared as some sort of electrical equipment and I was already with the floodgate equipment. Floodgate relay rooms look little different from other relay rooms, one or more racks of signalling relays and an illuminated track diagram. Floodgate equipment varies from apparently manually closed drop in gates (by winch I assume but I don't know), by platform and tunnel mounted motors driving gates into position, dropped from above by releasing catches etc. My recollection is that floodgate equipment, motors, pumps etc was often mounted in NPA passageways rather than rooms but it's 20 years since I was near or by an actual floodgate location and 15 years since I last saw the inside of a floodgate relay room.
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Post by Nortube on Apr 28, 2015 17:05:19 GMT
RT
Thanks I should have worn my reading glasses when looking at the diagram. That part of it that I'd printed out was a bit blurred. I did wonder if there was a basic speed measurement in the way you'd suggested. I suppose that it could be elsewhere in the speed indication circuit. I know that sort of method was used in various places under the previous signalling system on the Northern line, I think the more common way was the 4½ second delay before the signal cleared (one shot?) or, in some cases (such as terminus inner home AE100 (Edgware) and NU300 (High Barnet), the signal would not clear if the train was too fast and reached the blockjoint before the 4½ seconds was up, thus triggering another delay (dual shot?) before the signal cleared.
On the Guard and Motorman course, the mention of auxilliary track circuits was almost an afterthought and I think only included just to let us know that the movement of the train was capable of triggering other things. As you say, there was no need for the operating side to know any detail. I think that they thought it was enough for us to know the bell codes for a block telegraph!
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Post by railtechnician on Apr 29, 2015 8:25:13 GMT
RT Thanks I should have worn my reading glasses when looking at the diagram. That part of it that I'd printed out was a bit blurred. I did wonder if there was a basic speed measurement in the way you'd suggested. I suppose that it could be elsewhere in the speed indication circuit. I know that sort of method was used in various places under the previous signalling system on the Northern line, I think the more common way was the 4½ second delay before the signal cleared (one shot?) or, in some cases (such as terminus inner home AE100 (Edgware) and NU300 (High Barnet), the signal would not clear if the train was too fast and reached the blockjoint before the 4½ seconds was up, thus triggering another delay (dual shot?) before the signal cleared. On the Guard and Motorman course, the mention of auxilliary track circuits was almost an afterthought and I think only included just to let us know that the movement of the train was capable of triggering other things. As you say, there was no need for the operating side to know any detail. I think that they thought it was enough for us to know the bell codes for a block telegraph! Yep the one shot and two shot time circuits are two of the three methods of speed control that I am familiar with but as I suggested and as you rightly point out the speed determination is approximate and in effect is either less than (how much less generally cannot be determined but that does'nt matter!) or equal to the desired speed to safely clear the signal as it is approached or too fast as the train reaches the end of the timing section before the JR (time relay) has wound fully up and then has to wait for it to finish winding while waiting at a red signal. The third method is the inductor rail and FR (frequency relay) which is perhaps a more accurate gauge of actual speed as the FR is set to pick up at a specific speed (IIRC there are six types of FR i.e. 6 speeds 5 mph apart from 10 mph or 15 mph) say 25 mph although I wasn't doing anything like 25 mph when I was testing them by wiping the lid of a TDB (track disconnection box) along the inductor rail. That was enough to generate magnetically the correct level necessary low volt output which was boosted by the trackside amplifier to drive the FR.
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Post by hellocontrol on Apr 30, 2015 10:02:24 GMT
RT where you have put the Z in front of the number IIRC Z indicates something special? Yes Z means special and the number indicates which floodgate the telephone is associated with. RT thanks for confirming that.
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Post by hellocontrol on Apr 30, 2015 10:03:51 GMT
Early radar? From the Traffic Circular description and looking at the posted diagram in this thread, it would appear that no signals in this area are speed controlled. All that happens is that the speed indicator circuit is turned on / off by the occupation of a track circuit. This may be an example of what Rules and Regs used to teach as an 'Auxiliary track circuit' - a track circuit that was also used for other purposes as well as controlling a signal. Looking at the diagram, it would seem that the only part of the speed indicator circuit that is shown are the track relay contacts for track circuits 637a and 637a. The main circuitry for detecting and displaying the speed is not shown on the diagram and would be on diagram / sheet AS11949/12. If I'm following it correctly: When the first pair of wheels passes the blockjoint at FNX6371, track circuit 637a drops (the track is 'occupied') and this, amongst other things, closes contacts 7 and 12 on 637A track relay (637A TR), effectively closing two switches on the speed indicator circuit. The end result is that the train's speed will be displayed on the speed restriction sign. When the first pair of wheels passes the blockjoint at RFNX637, track circuit 637b drops and this, amongst other things, closes contacts 1, 2, and 5 on 637B track relay (637B TR), effectively closing a further three switches on the speed indicator circuit. After the last pair of wheels cleared FNX639, and thus track circuits 637a and 637b were back up (unoccupied), the speed indicator circuit would turn off. Nortube I was thinking the same as you but RT has pointed us in the right direction.
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Post by hellocontrol on Apr 30, 2015 10:05:57 GMT
RT I meant some of the relays that are only associated with the floodgates would have remained in the same position since the floodgates were last tested. Many years ago I went into one of these rooms and I am sure there was also another room which could not be accessed but looking through the window of the door it appeared as some sort of electrical equipment and I was already with the floodgate equipment. Floodgate relay rooms look little different from other relay rooms, one or more racks of signalling relays and an illuminated track diagram. Floodgate equipment varies from apparently manually closed drop in gates (by winch I assume but I don't know), by platform and tunnel mounted motors driving gates into position, dropped from above by releasing catches etc. My recollection is that floodgate equipment, motors, pumps etc was often mounted in NPA passageways rather than rooms but it's 20 years since I was near or by an actual floodgate location and 15 years since I last saw the inside of a floodgate relay room. I have been to a few of the sites well it was about 15 years ago and they were different for what reason I don't know.
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Post by hellocontrol on Apr 30, 2015 10:07:19 GMT
RT Thanks I should have worn my reading glasses when looking at the diagram. That part of it that I'd printed out was a bit blurred. I did wonder if there was a basic speed measurement in the way you'd suggested. I suppose that it could be elsewhere in the speed indication circuit. I know that sort of method was used in various places under the previous signalling system on the Northern line, I think the more common way was the 4½ second delay before the signal cleared (one shot?) or, in some cases (such as terminus inner home AE100 (Edgware) and NU300 (High Barnet), the signal would not clear if the train was too fast and reached the blockjoint before the 4½ seconds was up, thus triggering another delay (dual shot?) before the signal cleared. On the Guard and Motorman course, the mention of auxilliary track circuits was almost an afterthought and I think only included just to let us know that the movement of the train was capable of triggering other things. As you say, there was no need for the operating side to know any detail. I think that they thought it was enough for us to know the bell codes for a block telegraph! Nortube yes I remember being told various things about track circuits it all depended on the instructor some of them were really good.
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Post by Nortube on Apr 30, 2015 15:30:29 GMT
RT I meant some of the relays that are only associated with the floodgates would have remained in the same position since the floodgates were last tested. Many years ago I went into one of these rooms and I am sure there was also another room which could not be accessed but looking through the window of the door it appeared as some sort of electrical equipment and I was already with the floodgate equipment. I believe the 'another room' was one of those that either lead on from the IMR via a usually locked door, or are sited elsewhere, such as in the original C&SLRly passenger tunnel at Stockwell. My experience is that these often contain the higher voltage (some at 60v) equipment that is associated with the signalling / IMR, such as rectifiers, transformers and a range of other electrical equipment. There may also be some other equipment there as well, such as switches etc.
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