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Post by hellocontrol on Apr 23, 2015 14:22:56 GMT
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Post by hellocontrol on Apr 23, 2015 14:23:55 GMT
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Post by hellocontrol on Apr 23, 2015 14:24:45 GMT
Last bit.
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Post by hellocontrol on Apr 23, 2015 14:32:16 GMT
Chaps an interesting thread! As far as I know there never was a floodgate telephone at FNX639. The 'squashed D' as you call it is known to engineering staff as a 'Polo' and as you know is the indicator for the presence of a stick telephone. I recall the Ericsson Annunciator to which that phone was connected at London Bridge. During the JLE works there it was extant in a rather denuded subway passage of bare concrete and exposed segments when I was there diverting comms cables around the bulldozers in the running tunnel to Borough. I'm sure the stick phone at FNX639 would have remained in operation up until the Northern line resignalling otherwise it should have disappeared years ago (most station platform Ericsson Annunciator panels were removed in the late 1980s following the 1983 switch from Strowger electromechanical to MD110 digital telephone exchanges. That said there were still a couple around and working in the early 2000s with only stick phones connected to them. In the days when LT/LU did its own resignalling work we would have marked a decommissioned/redundant phone with a painted yellow cross (the symbol for 'comes out') on changeover night and/or either covered it up with sacking/black PVC or removed it on the night. The polo would have been removed or covered up. These days the signalling contractors are apparently allowed to get away with lower professional standards if that phone is now redundant! It has been a long time since I last looked at a floodgate, however, from the strip print a 'gate locked' relay drops when the floodgate is unlocked, the rail seals (hands up I cannot recall those at all!) are broken or the escape hatch is open. FNX6371 has the floodgate 20 and 22 'gate locked' relays in its selection as well as a controlling switch {which I assume existed to allow local testing of the floodgate(s)}. Either 'gate locked' relay dropping also extinguishes the FNX6371 'A' sign. I last recall seeing floodgates tested in the late 1970s, I remember one at Embankment being tested on a Sunday morning before start of traffic. Last I heard before retiring was that all the floodgates were secured locked and relevant contacts in signal selections bridged out as it was feared that some floodgates if operated, in particular like the ones that drop from the roof at Liverpool Street, would never be able to be normalised. Over the years I worked in a number of Floodgate relay rooms, Kennington, Moorgate, Liverpool Street, Green Park etc and one thing that they all had in common was old relays. Many were dated 1961 and nothwithstanding power outages the vast majority were permanently 'UP' for decades, only the delta relays in signal selections seeing regular pick up and drop away and generally those being the only relays that were changed as the carbon contacts wear out with daily operation. Since I retired I have heard that there were/are moves afoot to return floodgates to full operation but that was several years ago and of course would require a lot of work particularly on the Bakerloo where the resignalling involved breaking out concrete to make way for new cabling such that floodgates, even if they could be closed, would not be sealed! It's a shame there is only a partial strip print with both ends missing! I remember when I first went on the trains being told of the various signals and the phones which may be found. A squashed D was the main one with others being identified by the box/cabinet they were in and if there was a label on it. In later years when I worked on the station side if any phones or panels found always tried to see if anyone would answer and on one occasion at Elephant & Castle SB Northern there was a phone which said floodgate controller and for the fun of it I rang and someone answered which surprised me although they never said where they were.
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Post by hellocontrol on Apr 23, 2015 14:34:38 GMT
RT - there does seem to be various bits of equipment around that has been redundant for years where it is no longer used or there have been alterations (as at London Bridge and Angel) and it has been missed. I've seen many examples when driving / walking the line. I suppose that, in the scale of the works at London Bridge, a couple of missed signal phones and squashed Ds were minor There is lots of redundant comms kit around on the railway, typically and principally it is for one of two reasons (a) nobody wanted to take the responsibility of recovering the old until the new had been brought into service and proven its integrity and reliability (b) recovery was going to be expensive and with money for new projects being tight it was decided to await a bigger job such as line resignalling to recover all redundant kit in one hit. Some examples:- When the new depot shunters radio systems were installed at Oakwood and Northfields depots the old depot shunters loudspeaker systems were left in situ and hot! Thus they could be reinstated at short notice if necessary. I discovered them more than a decade after the radio systems were in use, 1950s valve amplifiers hidden in cupboards in the shunters cabins and still powered up. Indeed a new depot loudspeaker system was installed in a new east end shunters cabin at Northfields and both it and its new west end brother were redundant having never been in use, indeed last I heard the old and new west end shunters cabins were going to be demolished as part of a project to extend the train shed. Earls Court control room saw many improvements in technology over several decades but very little of the old technology was recovered. Not long before I retired I was asked to 'tidy up' the Picc and District controllers desks so that some new equipment could be installed, quite frankly few people had the 'bottle' to do it and they were afraid of disturbing anything, especially the outside contractors who were initially asked to do the work (there had been a train radio failure which resulted in trains having to be double manned and one or two other issues which made operational managers rather wary too but as I was a control room T/O there at the time and I was quite happy to take full responsibility). I recovered the original telephone panels and associated cabling and in the process reinstated some lost circuitry such as the Northfields sump alarm, I also recovered redundant cabling and power supplies within the two desks and the three desk pedestals and relocated working train radio and CCTV equipment to clear space in the desks before tidying all remaining wiring into a neat loom. I then went to the relay room and recovered all the equipment there including a redundant telephone rack which still carried the long redundant DRICO relay sets as well as the line relays for all the controller and regulator defunct direct telephone lines as well as the associated power supplies and ringing converters. I removed all the redundant strip connections from the main distribution frame releasing space for new cabling to be installed and tidied up other miscellaneous kit while I was there. I carted two van loads of redundant equipment back to the Picc comms stores at Acton. My engineering manager was more than happy as was the DLCM in charge of the control room but that was really the tip of the iceberg, I had identified plenty more redundant equipment and cabling and was told that I had done enough, indeed I was rewarded with £200 in vouchers for my efforts as I recall. Back in 1962 the Northern line tunnels at Old Street suffered corrosion from acid in the ground and had to be strengthened. During the work all the comms and signalling cables were diverted into the other tunnel and when replaced the outcome was that a lot of original scrap lead cable was simply left in the cable run. Some 30 years later the same section of tunnel was found to be seriously weakened and I was tasked to divert all the comms cabling to the other tunnel and then renew the cabling through the newly relined (expanded to a greater diameter) tunnel. In the process I recovered not only the scrap that I had created but also all the scrap cable left in situ in 1962. Fortunately we got a train out on a Saturday night and so we didn't have too far to carry the scrap cable which I got a licence to store in the suicide pit for a few days. Quite often odd things get buried or forgotten e.g. there are probably still a few items of comms kit in situ at Embankment including an Ericsson panel which was in a telephone room covered up by new panelling on the W/B DR, an original Ericsson magneto instrument in a room behind the panelling on the E/B DR, the original station PA valve amplifier on a disused overbridge (Paiges Walk) above a Bakerloo platform, Link Box 'F' in a long disused room off the lower circulating area beneath the DR to name but a few. That is one site but I can think of many where relics of days past will one day be discovered again by those who will know nothing about them and like the posters found at Waterloo in its 1980s refurbishment will excite members of a future generation! I have to say that from an operational standpoint it is unacceptable to leave a redundant 'stick' phone in place and not covered up or marked as redundant (a painted red cross). I am aware that such things as standards are no longer as strictly adhered to as they used to be, I first observed what I regard as sloppy practice at the south end of the Northern line in the late 1980s when the station upgrades were taking place and I was involved in temporarily relocating tunnel telephones as enabling work for the contractors. From that time onward contractors began installing new tunnel telephone equipment and teeing the phones to the tunnel lines instead of putting the phones in series with the lines as per standard safety practice. Although I highlighted it at the time I was told to ignore it even though a fault could render the telephone useless and be unable to discharge the traction as it should. For the same reason I refused to commission the Leicester Square operations room emergency T/T plungers until the contractor rewired them to standard. An in situ uncovered redundant 'stick' phone is not of course as bad as a T/T instrument or plunger that does not work but it could cause an unnecessary delay in taking action in an emergency! I recall installing new T/T headwall phones at Kings Cross Picc line in the late 1980s. I ran out of track time while commissioning the new W/B instrument and thus could not disconnect the old phone so for one day only there were two W/B T/T instruments wired in parallel. I was called into the Engineering Manager's office to explain myself after reporting the situation, he knew that the situation was safe and the integrity of the system was not compromised but he was worried that in an emergency the user would not know which instrument to use! I don't believe that, that level of concern exists today but it should, it really should ! RT as always your posts are really fascinating, shows what the job was like thanks. I feel sorry for those that are still working as it is not much fun anymore.
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Post by railtechnician on Apr 23, 2015 16:46:33 GMT
Hellocontrol, thanks for the strip print, I will peruse it and if you have any questions pertaining thereto I will be happy to answer them.
I certainly feel sorry for today's LU workforce, most will never have the opportunity to work all over the system in multiple disciplines as I did in those years that I will always regard as the last years of the greatest era of the Underground system when it was still run by engineers and real railwaymen. Many of the people that I learnt aspects of the job from in the days when it was run more like a military force than a business, as it is today, would surely be turning in their graves. We worked hard because the job was very disciplined and we quickly learned that our value to a supervisor was gauged by recent past performance i.e. one had not only to build a reputation as a useful employee but also to maintain it not only with one's managers but also with one's colleagues. I knew many a man that didn't last a month let alone manage three months probation and every shift was a test of one's mettle, new entrants being given the filthiest jobs in some of the worst areas of the railway under chargehands who were just as happy to get a new boy sacked as to teach him anything. One really had to put oneself out to get on and be accepted in those days, health and safety as we know it today did not exist when I began my LT career, one learnt to take the 'rough with the smooth' for those who complained about working conditions were given a four hour walk and summarily dismissed. Very few sent to Acton Town to explain themselves to the engineer returned to duty! That said, once one had learned the way of the world, become part of a gang, completed probation and been accepted things improved. The job was still graft and filth but there were rewards, asking meaningful questions in the right quarters got meaningful answers and those of us that wanted to learn and be more than just labourers attended voluntary evening classes to learn about signalling. Once a supervisor was aware that one was interested he was more disposed to explaining circuitry and systems when he had a spare minute or two. After a while and having demonstrated the skills for which one was remunerated to an acceptable level of competence one was trusted, thus promotion became an option. I began as a wireman but within a few months I was trusted to act as chargehand in his absence and was allowed to be a keyholder. I had taken a test for promotion but was not informed that I had passed for many months and then was rewarded with not only a pay rise but a nice wad of back pay too. Well that was Signal New Works in the late 1970s, by 1980 I had transferred to Telephone Installation and become a chargehand, chiefly due to the grade I had attained on signals but also because I was a trained PO telephone engineer before joined LT. After completing major CCTV and PA project work I moved to the training division for a few years teaching several skills to Signal, Telephone, LT Cables and HT Mains staff. In the late 1980s I was in Comms Installation installing CCTV, PA, Telephones, Train Radio and other related systems and became an acting supervisor, for a while I was in charge of the main cable uplift to increase the numbers of telephone and data circuits available on all lines. I also did some major cable diversion works and equipment relocations as part of the Central line enabling works before becoming the night Comms installation and maintenance supervisor responsible for tunnel telephone, stick telephone and section 12 PA 2,3 & 6 month maintenance schedules and a number of installation projects including CSDE surveys and CSDE installation. Crossrail was my last major project, with a staff of internal and external contractors I did the enabling works surveys of signalling, electrical, communications and services including plumbing and drainage at six stations. I then moved to Picc Line Engineering as the comms technical officer on permanent nights and then trained as a signalling technical officer to become a dual grade technical officer with duties including installation, maintenance, routine and emergency equipment change and staff training. Ill health took me off the track and I became predominantly a control room technical officer but also used to get out to all the IMRs and do the frame maintenance at all the Picc, District, Met sites that Tube Lines maintained.
It will soon be 10 years (July) since I retired and if I had not become sick I would still have more than two years service to complete a little over 41 years in the job. Sometimes I do feel somewhat cheated at missing the last third of such a career as I might have learned so much more. That said, I am pretty certain that if I had not taken early retirement when I did I would have been dead four years ago if not before. As it is these days I do wonder how I ever found the time to work because I don't have the time to keep up even a fraction of my many hobbies and interests!
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Post by hellocontrol on Apr 25, 2015 13:35:08 GMT
I will go through the diagram myself and I am sure that there will be some questions.
On the operating side there were some people that did not last but for very different reasons and some just moved elsewhere and as you moved up the ladder it got worse.
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Post by hellocontrol on Apr 26, 2015 14:45:43 GMT
RT first question on the diagram at Moorgate there is marked a dead section by the floodgate how long would this be and for what purpose? Now south of Bank there appears to be a dead section although not marked as such, is this the same?
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Post by railtechnician on Apr 26, 2015 17:31:12 GMT
RT first question on the diagram at Moorgate there is marked a dead section by the floodgate how long would this be and for what purpose? Now south of Bank there appears to be a dead section although not marked as such, is this the same? There are a number of dead sections shown other than at floodgates, these are 10' dead sections between adjacent tracks. There are two possibilities that spring to mind. Normally adjacent track circuits are electrically opposed in order to prevent a blockjoint failure between adjacent tracks from creating one long track circuit from the two i.e. to obviate the possibility of two tracks becoming series aiding which can cause other problems including putting the stick back in the face of a driver in the case of a blockjoint failure at a signal location. When I began my LT career there were dead sections on the Northern line to detect blockjoint failures. A 12v lamp connected the section rail from each adjacent track into the dead section, there being two blockjoints between adjacent tracks. If either blockjoint failed the blockjoint failure detector lamp would light but would not cause a track circuit failure as both blockjoints wouid have to fail to cause a track circuit failure. However, a blockjoint detector lamp could fail, if it went open circuit it couldn't indicate a blockjoint failure but if it went short circuit it would cause a track circuit failure. Thus blockjoint detector lamps were all removed but to this day there may still be 10' dead section as shown on the drawing because a train cannot be 'lost' in such a section. You may still see blockjoint detector lampholders in station areas, black rubber housings sometimes mounted at rail level in the suicide pit area or sometimes a couple of feet above on the wall! Blockjoint detectors were found on other lines too. The other possibility is an anti-opposition track, a 10' dead section with two blockjoints in each rail. Sometimes with the passage of time, rerailing and other works the opposition between adjacent track circuits would be lost and so one night task for signal New Works would be to 'put tracks to standard' i.e. bringing them back to correct specification in terms of materials, terminations, labelling etc. If adjacent tracks were not opposed that had to be corrected and it could mean many nights 'turning over' (rearranging the electrical connections) tracks one after another until all were correctly opposed. Sometimes it could be a lengthy process involving turning over the tracks through several stations. The anti-opposition track was a means of imposing a limit upon the amount of tracks that needed to be turned over because it didn't really matter if the two tracks on either side of an anti- opposition track were not in opposition ! I don't actually know how long the dead section at the floodgate is but I suspect no more than 10'. Note that gates 20 and 22 have the same arrangement of dead section although it is not actually declared as such. The purpose of the dead section is probably due to the need to make a good seal when the floodgate is closed making that short section of track electrically unsuitable to be part of the track circuit. That is the track circuit might be subject to fault due to the close proximity of the concrete profile that the floodgate closes to and the seal(s) that make the area around the rails watertight. Apparently the JLE has rubber seals at track level but I cannot say that I have ever noticed floodgate rail seals on any line. When track circuits are unoccupied the floodgates are mechanically unlocked and may operated to the closed position, conversely when track circuits are occupied the floodgates are mechanically locked and cannot be opened or closed. The dead section rail seal operation/detection in the floodgate circuitry would be shown in book wiring at the floodgate relay room. If you look at gate 20, 635 C track circuit sits either side of it. Below gate 20 and to the left is gate 20 lock valve magnet which when energized by 635 C unoccupied and Bell SR up unlocks the gate. Obviously 635 C TR 3's front contact drops with the passage of each train during track circuit occupancy and thus locks the gate until the train has passed. The Bell SR (stick relay) 3's front contact will normally be UP and remain so. If it drops the gate will remain unlocked so long as 635 C track is not occupied. I assume that the Bell SR is de-energised when the gate is about to be closed and presumably a warning bell sounds. The gate 20 locked relay is normally energised so long as the rail seals (I cannot visualise them, so I don't know if they move into place but I suspect that they do as they are detected) are normal, the escape hatch is closed (because it would probably foul the tunnel) and gate 20 is locked. FNX 637 cannot clear until FNX6371 is cleared and both signals require gates 20 and 22 to be locked before they can clear.
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Post by hellocontrol on Apr 26, 2015 18:40:56 GMT
RT first question on the diagram at Moorgate there is marked a dead section by the floodgate how long would this be and for what purpose? Now south of Bank there appears to be a dead section although not marked as such, is this the same? There are a number of dead sections shown other than at floodgates, these are 10' dead sections between adjacent tracks. There are two possibilities that spring to mind. Normally adjacent track circuits are electrically opposed in order to prevent a blockjoint failure between adjacent tracks from creating one long track circuit from the two i.e. to obviate the possibility of two tracks becoming series aiding which can cause other problems including putting the stick back in the face of a driver in the case of a blockjoint failure at a signal location. When I began my LT career there were dead sections on the Northern line to detect blockjoint failures. A 12v lamp connected the section rail from each adjacent track into the dead section, there being two blockjoints between adjacent tracks. If either blockjoint failed the blockjoint failure detector lamp would light but would not cause a track circuit failure as both blockjoints wouid have to fail to cause a track circuit failure. However, a blockjoint detector lamp could fail, if it went open circuit it couldn't indicate a blockjoint failure but if it went short circuit it would cause a track circuit failure. Thus blockjoint detector lamps were all removed but to this day there may still be 10' dead section as shown on the drawing because a train cannot be 'lost' in such a section. You may still see blockjoint detector lampholders in station areas, black rubber housings sometimes mounted at rail level in the suicide pit area or sometimes a couple of feet above on the wall! Blockjoint detectors were found on other lines too. The other possibility is an anti-opposition track, a 10' dead section with two blockjoints in each rail. Sometimes with the passage of time, rerailing and other works the opposition between adjacent track circuits would be lost and so one night task for signal New Works would be to 'put tracks to standard' i.e. bringing them back to correct specification in terms of materials, terminations, labelling etc. If adjacent tracks were not opposed that had to be corrected and it could mean many nights 'turning over' (rearranging the electrical connections) tracks one after another until all were correctly opposed. Sometimes it could be a lengthy process involving turning over the tracks through several stations. The anti-opposition track was a means of imposing a limit upon the amount of tracks that needed to be turned over because it didn't really matter if the two tracks on either side of an anti- opposition track were not in opposition ! I don't actually know how long the dead section at the floodgate is but I suspect no more than 10'. Note that gates 20 and 22 have the same arrangement of dead section although it is not actually declared as such. The purpose of the dead section is probably due to the need to make a good seal when the floodgate is closed making that short section of track electrically unsuitable to be part of the track circuit. That is the track circuit might be subject to fault due to the close proximity of the concrete profile that the floodgate closes to and the seal(s) that make the area around the rails watertight. Apparently the JLE has rubber seals at track level but I cannot say that I have ever noticed floodgate rail seals on any line. When track circuits are unoccupied the floodgates are mechanically unlocked and may operated to the closed position, conversely when track circuits are occupied the floodgates are mechanically locked and cannot be opened or closed. The dead section rail seal operation/detection in the floodgate circuitry would be shown in book wiring at the floodgate relay room. If you look at gate 20, 635 C track circuit sits either side of it. Below gate 20 and to the left is gate 20 lock valve magnet which when energized by 635 C unoccupied and Bell SR up unlocks the gate. Obviously 635 C TR 3's front contact drops with the passage of each train during track circuit occupancy and thus locks the gate until the train has passed. The Bell SR (stick relay) 3's front contact will normally be UP and remain so. If it drops the gate will remain unlocked so long as 635 C track is not occupied. I assume that the Bell SR is de-energised when the gate is about to be closed and presumably a warning bell sounds. The gate 20 locked relay is normally energised so long as the rail seals (I cannot visualise them, so I don't know if they move into place but I suspect that they do as they are detected) are normal, the escape hatch is closed (because it would probably foul the tunnel) and gate 20 is locked. FNX 637 cannot clear until FNX6371 is cleared and both signals require gates 20 and 22 to be locked before they can clear. RT I know the term dead section gave it away but I was not sure if these were specific in length and if they served any special purpose and the penny has dropped as like you say you would not want any circuits in that area dropped. I have seen a block joint detector at the Elephant on the NB Northern when an obstruction was put across it lit up. Now what you say about the floodgates leads to another question, how different was the circuitry between the different types of floodgates?
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Post by railtechnician on Apr 26, 2015 22:20:33 GMT
RT I know the term dead section gave it away but I was not sure if these were specific in length and if they served any special purpose and the penny has dropped as like you say you would not want any circuits in that area dropped. I have seen a block joint detector at the Elephant on the NB Northern when an obstruction was put across it lit up. Now what you say about the floodgates leads to another question, how different was the circuitry between the different types of floodgates? Now that's a question I cannot answer if you are referring to control and detection of floodgates, the associated pumps and related items such as gas detection etc. I haven't ever seen the drawings for that circuitry. As far as signalling is concerned the circuitry generally follows the line standard, however, as I mentioned upthread floodgate relay rooms are not well maintained because the floodgates are permanently locked open. You'll notice loops on the strip print which bypass (short circuit) floodgate signalling contacts such that they have no effect on line signalling i.e. the control switches for signal selections are looped out as are the rail seal detector contacts. The relays in floodgate relay rooms may have been in service for 50 + years now and are perhaps more prone to failure than other relays which were/are routine changed every few years. For standard signalling relays it was 7, then 10 years when I was changing relays but I heard some years ago that the time had been extended to 15 years and subsequently no routine change at all! The last relay I changed in a floodgate relay room was a delta and it wasn't that old as I recall, because it picked up with the passage of every train and then dropped away it was bound to wear out in a few years whereas most floodgate relay room relays never change state because the floodgates are not in use! It may well be, I don't know, that even where resignalling has taken place nothing in the floodgate relay rooms has been altered.
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Post by hellocontrol on Apr 27, 2015 13:01:44 GMT
RT I know the term dead section gave it away but I was not sure if these were specific in length and if they served any special purpose and the penny has dropped as like you say you would not want any circuits in that area dropped. I have seen a block joint detector at the Elephant on the NB Northern when an obstruction was put across it lit up. Now what you say about the floodgates leads to another question, how different was the circuitry between the different types of floodgates? Now that's a question I cannot answer if you are referring to control and detection of floodgates, the associated pumps and related items such as gas detection etc. I haven't ever seen the drawings for that circuitry. As far as signalling is concerned the circuitry generally follows the line standard, however, as I mentioned upthread floodgate relay rooms are not well maintained because the floodgates are permanently locked open. You'll notice loops on the strip print which bypass (short circuit) floodgate signalling contacts such that they have no effect on line signalling i.e. the control switches for signal selections are looped out as are the rail seal detector contacts. The relays in floodgate relay rooms may have been in service for 50 + years now and are perhaps more prone to failure than other relays which were/are routine changed every few years. For standard signalling relays it was 7, then 10 years when I was changing relays but I heard some years ago that the time had been extended to 15 years and subsequently no routine change at all! The last relay I changed in a floodgate relay room was a delta and it wasn't that old as I recall, because it picked up with the passage of every train and then dropped away it was bound to wear out in a few years whereas most floodgate relay room relays never change state because the floodgates are not in use! It may well be, I don't know, that even where resignalling has taken place nothing in the floodgate relay rooms has been altered. RT I did not mean all the other equipment just the floodgate circuits, some of those relays must have been in the open position for years and other than when the signalling was tested. Testing of the floodgates ceased many years ago so the rooms would be a hazard.
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Post by railtechnician on Apr 27, 2015 13:20:17 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.
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Post by Nortube on Apr 27, 2015 20:02:11 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 enlarge
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Post by Nortube on Apr 27, 2015 20:08:53 GMT
Whilst on the subject of floodgates, an entry from TC44 1940 re the operation of the Charing Cross Floodgates on the District line, plus a couple of other tit bits click on the photos to enlarge
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