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Post by Nortube on Nov 16, 2016 11:13:44 GMT
The disused siding at London Bridge was a possible option as, unless it had already been used by the time IMRs were added, there would have been space there although it may have blocked off the siding. It's possible that, like Moorgate etc, it may have led off the platform. Trying to picture the platform from a Guard's point of view before the crossover was closed and the Jubilee started building there, I vaguely recall that there was a building at the south end of the NB platform, do it's possible that that may have been the location. Even if the IMR was in the siding, it may not have had a second door. Many on the Northern line didn't and I think that in many cases a second door was just there for convenience rather than to be used an emergency exit. Some IMRs were very confined with relays etc. being within easy reach when passing. Camden Town, where the IMR is lengthwise at the end of the platform, is an example of this. The main door off the platform led past banks of equipment to the frame at the end. I seem to recall that there was also a movable ladder there a well to access the higher relays. To the right of the frame, a door opened up to the narrow part of the platform. This door was a convenient access for whoever was working the frame without having to squeeze past the equipment every time. Indeed, it may well have been the designated access point for people operating the frame. On the few occasions of a major signal failure that meant Camden had to be manually worked from the frame, it could be rather busy there As far as I know, the IMR on platform 1 was the only one at Camden Town. This contained the frame that controlled Camden Junction and the Mornington Crescent crossover (all 'E' signals). It's possible that there may have been a relay room elsewhere.
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Post by Nortube on Nov 17, 2016 9:08:12 GMT
My vague recollections were correct! The IMR at London Bridge was on the far south end of the NB platform.
I've updated the list and also added Golders Green South which I missed out.
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Post by Nortube on Nov 17, 2016 10:18:56 GMT
Whist on the subject of IMRs, is the definition of Interlocking Machine Room as somewhere that the frame interlocking takes place by remote control? I.e. the physical interlocking that has, for convenience, a signal lever frame attached so that the interlocking can be controlled via signal levers if required.
All the IMRs I've seen contain relays, fuses, programme machines (and sometimes a describer drum) / computer (if applicable) and the remote interface circuitry etc. Whilst some of these may be directly linked to the interlocking operation, I assume that the most of the relays and many of the fuses are the track relays and track fuses that would normally be located at track level, but are all grouped together in the one place for quick and convenient access when fault finding. In effect, the IMR is also the local relay room. I assume that, if space is tight, the track relays and fuses could be located in a separate relay room elsewhere.
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Post by railtechnician on Nov 17, 2016 12:08:18 GMT
The disused siding at London Bridge was a possible option as, unless it had already been used by the time IMRs were added, there would have been space there although it may have blocked off the siding. It's possible that, like Moorgate etc, it may have led off the platform. Trying to picture the platform from a Guard's point of view before the crossover was closed and the Jubilee started building there, I vaguely recall that there was a building at the south end of the NB platform, do it's possible that that may have been the location. Even if the IMR was in the siding, it may not have had a second door. Many on the Northern line didn't and I think that in many cases a second door was just there for convenience rather than to be used an emergency exit. Some IMRs were very confined with relays etc. being within easy reach when passing. Camden Town, where the IMR is lengthwise at the end of the platform, is an example of this. The main door off the platform led past banks of equipment to the frame at the end. I seem to recall that there was also a movable ladder there a well to access the higher relays. To the right of the frame, a door opened up to the narrow part of the platform. This door was a convenient access for whoever was working the frame without having to squeeze past the equipment every time. Indeed, it may well have been the designated access point for people operating the frame. On the few occasions of a major signal failure that meant Camden had to be manually worked from the frame, it could be rather busy there As far as I know, the IMR on platform 1 was the only one at Camden Town. This contained the frame that controlled Camden Junction and the Mornington Crescent crossover (all 'E' signals). It's possible that there may have been a relay room elsewhere. My recollection is that at least one signal equipment room at Camden Town was built in a disused exit subway and included the stairs up from a cross passage but I haven't been there since the late 1970s when fitting out the base of a disused lift shaft as a CER. In general terms there is only one IMR at a site, however, it is dependent upon the complexity of the track layout and the related flexibility in terms of train movements i.e. routes, thus Golders Green had North and South IMRs and Acton Town had East and West IMRs. In such circumstances routes are 'slotted' where parts of routes are controlled by levers in both IMRs. This is also the case at places like King's Cross where slotting of routes via the loop links Picc and Northern IMRs to control the movements from KX Picc to/from Euston Northern.
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Post by railtechnician on Nov 17, 2016 13:36:29 GMT
Whist on the subject of IMRs, is the definition of Interlocking Machine Room as somewhere that the frame interlocking takes place by remote control? I.e. the physical interlocking that has, for convenience, a signal lever frame attached so that the interlocking can be controlled via signal levers if required. All the IMRs I've seen contain relays, fuses, programme machines (and sometimes a describer drum) / computer (if applicable) and the remote interface circuitry etc. Whilst some of these may be directly linked to the interlocking operation, I assume that the most of the relays and many of the fuses are the track relays and track fuses that would normally be located at track level, but are all grouped together in the one place for quick and convenient access when fault finding. In effect, the IMR is also the local relay room. I assume that, if space is tight, the track relays and fuses could be located in a separate relay room elsewhere. An IMR controls the local routes by levers and as such can be worked manually from the frame when necessary, it uses both mechanical and electrical interlocking and may also be computer controlled locally with software interlocking. In modern systems such as that on the 1990s Central resignalling and JLE original signalling the lever frames were removed thereby removing the mechanical safety interlocking at the interface between non-safety and safety signalling circuitry. The original concept of an IMR was a place which controlled all the semi-automatic routes within an area, semi-automatic routes generally being those routes including sidings, crossovers etc i.e. routes containing points. The lowest level of interlocking was mechanical at points with groundlocks, originally before IMRs there was also mechanical interlocking of signals with 'slotting' at the signal posts and in the mechanical links to points and signals and of course trainstops are also mechanical interlocking. The next level of interlocking was electrical interlocking via track and signal relays, then the mechanical interlocking of the frame levers. All this is safety interlocking allowing the area to be controlled from the frame. The frame could be controlled either remotely by a signal operator ('push mode') in a local or remote location or by local programme machines working automatically from the timetable in 'programme mode' or according to incoming Train Description or where a junction was controlled in 'first come first served' if for some reason the timetable was incorrect or remote control was lost. The non-safety control of the frame was subject to IMR on site non-safety electrical relay, electronic card interlocking or computer interlocking, the remote control of which by a signal operator was also interlocked at the remote control point. Generally an IMR would contain all the elements necessary for full interlocking and control of a site but that was by no means always the case, nor did it need to be. Ealing Broadway is a good example of what a 'distributed' IMR once was when locally controlled from a pushbutton console in the tower above the relay rooms. Originally the site was a signal cabin with a signal operator, thus it had a lever frame controlling the District and Central lines behind which is the signal cabin relay room and which became 'the IMR' with local control such that the frame was normally unmanned. The cabin relay room was large but heavily populated with safety relays, incoming and outgoing fuse bays, feed fuse bays etc and so a new room was *built to contain the necessary remote control non-safety equipment, known as 'the TD room' because it contained the train describer equipment, it housed the lever operation boards (electrical interlocking of signal levers) and electronic interlocking for the pushbutton console and programme machines not only for Ealing Broadway IMR but also for Hanger lane Junction IMR. Subsequently remote control of Ealing Broadway was split between the Central (not sure if it was Leicester Square or Baker St then) regulating room and the Earl's Court District regulating room (later to become the District & Picc control room) with necessary slotting controls for transfer of stock between the lines. Thus additional equipment, high speed scanning, was installed to connect Ealing Broadway to the two regulating rooms and enable remote control of the site by Central and District regulators. Of course with the 1990s Central line resignalling the frame levers for Central line signal routes, except those required for stock transfer, were decommissioned as was the Central line high speed scanning rack and the IMR became a District IMR controlled only from Earls Court while a new SER was built along the track for the control of the Central line part of the site and subsequently the link between District and Central has been lifted, the slotting never worked properly after the Central was resignalled. We used to have to manually work all the District and Central signalling to transfer stock ! *the room may have already existed as a TD room but this was all before my days with LT/LU From the above you should see that Hanger Lane Junction IMR might also be seen as a 'distributed IMR' as its P/MCs are at Ealing Broadway. In the same vein Acton East IMR has/had control over both Acton West IMR and Ealing Common IMR as it housed all the P/MCs for the Acton area and also had the main slow speed scanning equipment for site control and repeated the necessary controls to bothe Acton West and Ealing Common. In that case I would call Acton East IMR a 'tandem IMR'. ***Do note that 'distributed IMR' and 'tandem IMR' are my terms for these sites and NOT LT/LU terms*** However, I use them to make the point that an IMR may or may not be self contained and may or may not have some form of control over the remote control of another IMR. I am simply pointing out that although an IMR may be a collection of safety and non-safety interlocking equipment in one room or location it is not necessarily the case, nor does it need to be, although it generally is particularly for the more modern sites which were purpose built as IMRs. In terms of the marshalling of trackside equipment, modern practice is to house as many traditional 'trackside' equipments in station relays rooms and IMRs rather than at trackside otherwise such generally have to be repeated (GVCRs, ALRs, TPRs, TPPRs, KLPPRs, GPRs, PRs etc) to bring the necessary detection circuitry into the IMR. Thus modern IMRs and relay rooms also house the track feed arrangements for track circuits that would have traditionally been fed from local trackside locations. The bottom line is that there is no definitive standard for IMRs although there are standards for all the parts thereof and that is why we always said that every IMR is unique. Believe me when it comes to equipment details there are differences at all levels which even with identical track layouts, identical track, point and signal designation etc at two different locations on the same line each IMR would most probably be unique one way or another!
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Post by dave1 on Nov 17, 2016 14:30:01 GMT
RT An excellent post perhaps you could be persuaded to give us a better understanding on LU signalling I for one would not mind having lessons in the various areas.
Would I be right in saying that a programme machine could be termed just like an operator although only being able to do the things that are on the roll and not like a human change their minds?
The other thing is can you explain what these abbreviations stand for and what do they do.
GVCRs, ALRs, TPRs, TPPRs, KLPPRs, GPRs, PRs
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Post by railtechnician on Nov 18, 2016 9:57:22 GMT
RT An excellent post perhaps you could be persuaded to give us a better understanding on LU signalling I for one would not mind having lessons in the various areas. Would I be right in saying that a programme machine could be termed just like an operator although only being able to do the things that are on the roll and not like a human change their minds? The other thing is can you explain what these abbreviations stand for and what do they do. GVCRs, ALRs, TPRs, TPPRs, KLPPRs, GPRs, PRs The P/MC routes trains according to the timetable on the roll but when things get out of step due to failure the signal operator can switch from programme to first come first served and trains will be routed according to train description, any missing trains (i.e. taken out of service, turned short etc) get stored and can be routed out of turn if they subsequently appear although there is only a limited amount of storage which IIRC is a maximum of 5 trains to route 1 and 5 trains to route 2 at a diverging junction, after that stored trains have to be manually cancelled by the signal operator. When in programme only mode any unexpected trains result in alarms being raised in the regulating room to alert the signal operator and enable her/him to make a decision about where to send it. A P/MC is effectively out of service (OOS) when its YUPPR (disengaging route repeating repeating relay) is down, i.e. the signal operator has taken control by selecting push mode to manually control what would otherwise be controlled by the P/MC. There is a Master YUPPR which will disconnect all P/MCs in a room in the event of a system failure. The first thing to learn about LT signalling is the railway signalling alphabet and then you should be able to work out what relays do from their designations. In the designations that I gave A= Approach, C= Checking or Proving, G= Signal, K= Indication, L= Locking, P= Repeating, R= Relay, T= Track, U= Route, V= Trainstop or Valve, W= Point, Y= Disengaging Thus GVCR = Signal & Trainstop Checking Relay (when the signal is red and the trainstop is fully up it will be operated / UP) ALR = Approach Locking Relay (can have exactly the same function as GVCR, normally UP it will be DOWN when a train is within sighting distance of a signal and thereby prevents the selection of conflicting routes) TPR and TPPR = relays that repeat the action of a track relay (TR) directly or indirectly, ISTR that at Acton Town there is a TPPPPR but such also appear as TP 1R, TP 2R etc where say two relays repeat the action of a relay. KLPPR = relay that repeats the point indications of the contacts in the mechanically driven Point and Lock Detection box at a turnout or crossover, seen in older IMRs, more modern IMRs use WKRs and such designations as W(N)KR, W(R)KR and WLKR. GPR = relay repeating a GR (signal operating relay), not to be confused with a PGR which is a Repeating Signal operating Relay ! PR = Repeating relay, these will have designations such as 1070PR (repeating a WKR for 70W) or say 1005PR repeating a specific selection contact chain if it is not repeating a track or signal relay. There is of course much more to the railway signalling alphabet, all letters from A to Z are used and each letter can have a different meaning dependent upon its place within a designation string. For example N= Normal but also N= Hand Release so in older signal cabin relay rooms one would see designations such as JNNR, a relay that repeated the UP function of the release handle after it had been manually wound for one minute by the signal operator. You should deduce that J= Time The modern designation for point lock is WL and such is seen for the point lock wiring on outgoing fuse bays but in older LT signalling the designation was WJ just as an older near equivalent of a GVCR was a GMR (signal marking relay) on the east end of the Picc which originally used 50 volt signalling circuitry. Non-safety signalling uses all the same alphabetical designations and there you'll find designations such as DGKR and RGVKR which repeat trackside signalling functions, I'll leave you to deduce those functions!
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Post by dave1 on Nov 18, 2016 13:11:43 GMT
RT Excellent many thanks I look forward to the next lesson. I found this Alphabet for NR but nothing for LU page 16.
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Post by railtechnician on Nov 18, 2016 13:54:13 GMT
RT Excellent many thanks I look forward to the next lesson. I found this Alphabet for NR but nothing for LU page 16. Exactly the same alphabet ! Exactly the same nomenclature for electrical supplies too ! There may be one or two very slight differences in terms in the NR alphabet but the functions are all the same. Railway signalling standards are fairly universal although the technology varies around the world. Most drawings I have come across for other railways in the world use the same basic alphabet and of course the IRSE is a worldwide body universally recognised by all railways as the professional body for railway engineers and technicians. If you can read a LUL signalling drawing you can read any other railway drawing although other information may be required to make complete sense of any signalling diagrams, e.g. type(s) and dimensions of rolling stock, the different types of point machines, the variations in remote control systems etc etc
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Post by dave1 on Nov 18, 2016 14:55:43 GMT
RT Thanks for that.
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Post by Nortube on Nov 25, 2016 18:37:07 GMT
Northern line IMR locations I think I may have posted these on here before, somewhere. With the advent of the new signalling, they’re no longer relevant anyway From memory: Morden: Staff car park adjacent to platform 5, via car park and via end (handy to look out over the pointwork area Tooting Broadway: South end of NB platform. I can’t remember if there is an additional exit via the power room to the SB track Clapham Common: above the north end of the island platform, via steps from the crossover Stockwell: at the North end of the disused siding, via north end of SB platform Kennington: South end between platforms 1 / 3, via cross passage London Bridge: On south end of NB platform, via platform Moorgate: North end between platforms, via NB platform Euston City: above the south end of the original island platform, via steps from the crossover Camden Town: South end of platform 1, via platform (via relay section to frame) and via narrow platform edge (frame end – handy for the frame operator to stick his head out and look up the junction!) Archway: Off SB side of SB platform, via SB platform Highgate depot: In depot adjacent to Tamping Rd, via depot walkway. Technically it’s a Relay Room, not an IMR. Manual operation of the depot if required being carried out from the DMT’s office at East Finchley East Finchley: North of platforms, adjacent to NB running line, via staff area. Frame above Finchley Central: Adjacent to SB running track south of platforms, via track. Frame above Woodside Park: None – had ground frame south of the SB platform High Barnet: At south end of SB sidings, via sidings walkway. Frame above Charing Cross: North end of SB platform, via SB platform past frame area Hampstead: NB end of the platforms Golder Green North: South of platform 1, adjacent to substation, via platform 1 / works area Golders Green South: In depot, via depot walkway Colindale: off NB end of the platforms, via the platforms Edgware: Adjacent to platform 1 approach, via staff area Nortube If London Bridge was in the siding I wonder how they got out via another entrance, Camden Town was there another IMR somewhere else? I've updated my original listing to include the London Bridge location and also Golders Green North and South IMRs. I thought I'd done this, but I amended a quoted post of it instead! I've also added the area that was controlled from each of the two Golders Green IMRs
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drico
Station Inspector
Thank you driver, off clips.
Posts: 202
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Post by drico on Nov 25, 2016 18:57:30 GMT
Finchley Cental was next to the Northbound Line.
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Post by Nortube on Nov 25, 2016 19:27:01 GMT
Thanks - my mistake, a typo. Now corrected
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Post by railtechnician on Nov 26, 2016 11:05:02 GMT
My recollection is that Clapham Common ceased to be an IMR before I joined LTE. AFAIR the crossover pointwork removal took place circa March 1977 about six weeks before I started. I worked there soon after clearing up the remaining rubbish and redundant wiring from the changeover in what was then a spacious very empty room which AFAIK was then just a relay room. I then spent a few weeks at the three Claphams and Stockwell 'turning tracks over' and 'putting them to standard' to restore the anti-opposition tracks to the proper locations and finally completed that stint with a Monday night overtime shift replacing a signal head some distance from Stockwell. I can't recall the road, the direction or the signal but I have never forgotten my very bruised shoulder from that first tunnel signal head that I ever carried. In the early 1980s I recall routing telephone lines through the Northern and at Clapham Common the link box was on the back wall (in the tunnel) of what had once been the signal cabin relay room, the IMR above having once been the signal cabin. We used to have to duck into the tunnel to reach that link box and then quickly follow a train to get back to the platform as was the case for many tunnel sites back then. In the late 1980s I was at Clapham Common again updating PA & CCTV equipment and routing PA control lines through the new telephone cables laid as part of the Northern line telephone cable renewal but I never had occasion to look in the former IMR as all the comms kit was in the cathedral like invert beneath the platforms.
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