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Post by paterson00 on Aug 5, 2010 4:15:36 GMT
Can anyone explain to me why stick paths are used, highlight some common ones and explain why they are used and to make it even clearer, possibly upload a couple of typical stick paths to help explain it all?
Yours in hope..
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Post by railtechnician on Aug 5, 2010 16:57:32 GMT
Perhaps you should first be asking "What is a stick circuit?" !
In its simplest form a typical relay 'stick circuit' is a relay held energised ('UP' for signalling, 'operated' for other disciplines) only over its own contact such that when it is de-energised ('DOWN' for signalling, 'released' for other disciplines) it remains so until it is 'PICKED UP' (re-operated) by making some external contact as a result of some other circuit operation.
Assume the relay required to 'stick' is relay A and another relay B, when energised, is used to 'PICK UP' A. So to PICK UP A we energise B and the UP contact of B then energises A. A holds over its own 'UP' (also known as 'FRONT' in signalling, 'make' in other disciplines) contact such that B can be de-energised ('DROPPED' for signalling, 'released' for other disciplines) without DROPPING A. If A is then DROPPED it will stay down until relay B is re-energised.
Now what is a stick circuit good for? The most obvious use is in conventional LT capacitor fed track circuits where the replacing track of an automatic signal uses a trainstop proving circuit. Taking our example above relay A is the replacing track relay (TR) and relay B is actually the 'ON' contact in a trainstop. The TR is stuck UP until the replacing track is shunted by a train passing the associated signal, then it drops, this action indirectly causing the trainstop to come to the fully 'ON' position and the signal to change from green to red. The TR cannot pick up again until (1) the train has left the 'track' and (2) the trainstop comes to the fully 'ON' position. Think about what happens if the track remains shunted or the trainstop is obstructed and doesn't come to the fully 'ON' position!
There are lots of examples of stick paths in signal circuits, check the site prints when you get a spare minute or two. Look for the TQ circuit as briefly expalined above and see what I left out between it and the red (RE) and green (DE) signal lamps.
You can also look at stick relay (SR) circuits though there aren't too many about these days but they do crop up in IMRs where there are sidings with 'throw off' switches (points). Also approach lock relay (ALR) circuits and signal & trainstop checking relay (GVCR) circuits. There are others such as used in route securing (AWLR) and some that don't readily spring to mind at the moment!
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Post by paterson00 on Aug 6, 2010 13:44:42 GMT
"There are lots of examples of stick paths in signal circuits, check the site prints when you get a spare minute or two. Look for the TQ circuit as briefly expalined above and see what I left out between it and the red (RE) and green (DE) signal lamps. "
Where would i find the site prints? Ahh, I take it you mean on site rather than on this website?
Is there anywhere I can study typical circuits while i am indoors rather than at work?
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Post by railtechnician on Aug 6, 2010 17:00:07 GMT
"There are lots of examples of stick paths in signal circuits, check the site prints when you get a spare minute or two. Look for the TQ circuit as briefly expalined above and see what I left out between it and the red (RE) and green (DE) signal lamps. " Where would i find the site prints? Ahh, I take it you mean on site rather than on this website? Is there anywhere I can study typical circuits while i am indoors rather than at work? I assumed that you work at Metronet or Tube Lines and in one of the signalling sections, if so site prints are located at the respective relay rooms and IMRs etc or sometimes they've been removed to the local maintenance TO depot, convenient for the local TOs and also tends to ensure that 'visitors' introduce themselves before wandering around an IMR. Prints for all sites are held at the relevant Line Maintenance SOMs offices as an aid to assisting TOs on site with remote fault diagnosis. All these strip prints, bookwirings and miscellaneous other drawings are controlled copies and kept up to date but unless you are of a significant grade and/or supervised by a TO or SOM you may have difficulty accessing them.
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Post by paterson00 on Aug 7, 2010 5:41:32 GMT
Im currently working as a Mod 5 on the Jub but dont tell anyone I think we are getting bad press at the moment.
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Post by railtechnician on Aug 7, 2010 12:23:27 GMT
Im currently working as a Mod 5 on the Jub but dont tell anyone I think we are getting bad press at the moment. I haven't a clue what a MOD 5 is, I've never heard of such a grade. What exactly do you do currently?
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mrfs42
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Post by mrfs42 on Aug 7, 2010 12:50:05 GMT
Treadle circuits also use stick relays: the treadle is only activated intermittently, so a stick circuit is used to 'latch' UP [1] the treadle relay, giving a constant feed and bridging out the treadle circuits.
By and large stick circuits are used to 'remember' a particular set of conditions. Once the desired conditions have been met, the relay picks up and the stick path is made latching the SR up. It then doesn't matter what happens to the circuit conditions in that branch of the circuit as the stick contact bypasses the variable bits.
There will be another control of some form (perhaps a back contact further down the track) that will force the SR to drop and resetting the stick part.
[1] latching circuits or stick and stay circuits are at some point self-energising, there will be a front contact called [something, something]SR giving a paralled feed to a relay coil of the same name.
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Tom
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Post by Tom on Aug 7, 2010 12:53:40 GMT
Im currently working as a Mod 5 on the Jub but dont tell anyone I think we are getting bad press at the moment. I haven't a clue what a MOD 5 is, I've never heard of such a grade. Mod 5 is the shortened term for (Network Rail) Signalling Works Testing Handbook Module 5. The module 5 course is designed for people who are working towards, or as Test Assistants.
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Post by mrfs42 on Aug 7, 2010 14:27:52 GMT
I *knew* if I looked hard enough I coud find a simple example - perhaps not typical, but straightforward: 605CSR - Code Stick Relay unit. The circuit looks a bit more complicated than normal, as in common with 'old school' Victoria line signalling, if it could be double-cut it was! However the important bits to illustrate a stick circuit are in red circles below: If the path 605 CTR, 605 BTR, 605 ATR, 603 CTR, 603 BTR and 603 ATR is complete in both the BX and NX paths, then 605CSR will pick up. This is where the bits in red circles come in: these are front contacts of 605CSR. Once the circuit has been made and the relay has picked; the front contacts of 605CSR in red circles bridge out both 603 BTR and 603 ATR. Therefore even if 603 BTR and 603 ATR drop there will still be a feed to 605CSR via the circled front contacts. 605CSR would be dropped by any of 605 CTR, 605 BTR, 605 ATR, 603 CTR dropping, and then the circuit would reset itself.
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Tom
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Post by Tom on Aug 7, 2010 16:55:59 GMT
Who's been reading Challis then?
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mrfs42
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Post by mrfs42 on Aug 7, 2010 18:37:15 GMT
Only the first edition, I'm afraid. ;D Must chat to you sometime about the second ed. Was it ∆s on the Brixton extension?
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Post by railtechnician on Aug 7, 2010 19:54:20 GMT
I haven't a clue what a MOD 5 is, I've never heard of such a grade. Mod 5 is the shortened term for (Network Rail) Signalling Works Testing Handbook Module 5. The module 5 course is designed for people who are working towards, or as Test Assistants. Thanks Tom, obviously things have moved on somewhat in the last five years. Mind you I find that (MOD5) in itself no indication of job grade, on the Picc it was policy to teach the lowest grades (support techs and MDTs) to be test assistants which was IIRC the lowest form of IRSE license at that time. Those that worked with me were kept busy as I did lots of cubic foot prime safety critical relay changing on the Picc and Jub following an issue you might recall as a result of a failure caused by poor vane bearings. I was a licensed signalling tester until I retired but that license was abandoned and split down into three licenses AFAIR for those colleagues whose licenses were up for renewal circa 2004 and I can recall acting as a test assistant myself for those colleagues in the Wembley Park depot who were taking the replacement maintenance licenses. I haven't looked at the IRSE website for years but I expect I'd notice a lot of changes to licensing now.
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mrfs42
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Post by mrfs42 on Aug 7, 2010 21:42:14 GMT
As I've been sorting out images, I've found a couple more that you might find of interest: These are not of current practice..... I've not said what happens in them so you can have a ponder on them.
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Post by railtechnician on Aug 7, 2010 22:20:21 GMT
Cripes those are old and by the look of them were obsolete when the drawings were current.
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mrfs42
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Post by mrfs42 on Aug 7, 2010 22:32:55 GMT
I think they date from 1939; the penwork is almost the same as a 1926 example.
However, a stick circuit is a stick circuit. The drawings were "current" until 1994.
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Post by railtechnician on Aug 7, 2010 23:06:56 GMT
I think they date from 1939; the penwork is almost the same as a 1926 example. However, a stick circuit is a stick circuit. The drawings were "current" until 1994. Yep, quite so but I wonder what will be made of the open fuseholder terminals! Actually I should have dozens of stick circuit examples, I've just been looking at a USR pushbutton circuit for example that I drew more than 30 years ago when practising before taking a trade test to become a Tech 3(E) ! What I ought to do is get a photo site up again and scan in some circuits but I'm always busy with my other hobbies.
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mrfs42
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Post by mrfs42 on Aug 7, 2010 23:13:24 GMT
Yep, quite so but I wonder what will be made of the open fuseholder terminals! The fuses had been replaced with wooden dowels!
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Tom
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Post by Tom on Aug 7, 2010 23:39:17 GMT
I think Railtechnician refers to the fact that the circles haven't been shaded in!
I won't even start on the fact the fuse position hasn't been shown - I'm so glad we've moved away from those days and adopted some decent cross-referencing at last. I'm not so sure the preparers whose work I spent last week checking will agree with me though...
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Post by railtechnician on Aug 8, 2010 2:51:22 GMT
I think Railtechnician refers to the fact that the circles haven't been shaded in! I won't even start on the fact the fuse position hasn't been shown - I'm so glad we've moved away from those days and adopted some decent cross-referencing at last. I'm not so sure the preparers whose work I spent last week checking will agree with me though... Actually that was one point, also the fact that there is no reference to the circuits being out of commission, usually indicated with an X decorated with four dots or similar cipher between the fuse terminals. However, I expect an untrained eye will wonder how a circuit works without fuses! I've worked in many a relay room where the prints didn't show fuse positions, one of my regular sites was Ealing Common and that had many fuse positions omitted from the drawings but it wasn't as bad as Hanger Lane Junction where we used to pencil the fuse positions into the bookwiring as we found them! In this day and age I'd have expected new signal drawings to be produced on CAD and to be of a very high standard. There were definitely periods where some of the old hand drawn drawings were very rough indeed. I'd have loved a job in the DO but I so loved to be on or about the track and I always preferred nightwork.
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Post by mrfs42 on Aug 8, 2010 12:58:52 GMT
OK then - the last one from this particular bookwiring: It has a dotted X to shew the fuses have been removed and replaced with a wooden dowel, and a θ [1] shewing that the relay was removed. [1] Greek Letters crop up in all sorts of places on LT; I've seen Φ, Θ (uppercase theta), ∏ and ∆ all used for rail circuits on the 1926 Camden Town cabin diagram. Until the advent of position detectors you'd only get ∆s after about 1936/7.
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Post by railtechnician on Aug 8, 2010 14:14:10 GMT
OK then - the last one from this particular bookwiring: It has a dotted X to shew the fuses have been removed and replaced with a wooden dowel, and a θ [1] shewing that the relay was removed. [1] Greek Letters crop up in all sorts of places on LT; I've seen Φ, Θ (uppercase theta), ∏ and ∆ all used for rail circuits on the 1926 Camden Town cabin diagram. Until the advent of position detectors you'd only get ∆s after about 1936/7. Yep I've seen greek letters on a few prints. Obviously delta is common and doesn't beta occur on the Vic?. As for the Northern, a post run supervisor that I worked alongside back in the 1980s when I was an instructor at the South Woodford new works school used to talk about a Pi Delta circuit which IIRC correctly was something to do with a siding at Archway. I think Ealing Broadway and South Harrow probably still have plenty of dead circuits shown in the prints (bearing in mind I haven't seen them since 2004) and lots of dummy relay frames. South Harrow certainly still had its plate racking and links. I think that practice was outlawed long ago but it was all the rage in my earliest days on signal new works. I recall shifting a mass of plate rack links in the tunnel at Baker Street when the old Bakerloo branch became the Jubilee (I also recall having to change contacts in the trainstops from 'Off to On' contacts or vice versa on the changeover, another practice long since dropped through standardisation) and at Cockfosters on the stage 1 changeover the plate rack was trackside in a kiosk outside the cabin, it had dozens of links to shift 'on the night'. I'm wondering if all the links shown on that drawing are associated with the power frame or if they are plate rack terminals, I suspect the former but it's very poor practice for them to be undesignated terminals.
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mrfs42
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Post by mrfs42 on Aug 8, 2010 16:09:56 GMT
I'm not sure about the Pi Delta at Archway - but I'll look into it. EDIT: there wasn't a ∆ in the siding with the extension opening [unlike the Bakerloo takeover of the Stanmore branch a few months later, which *did* have ∆s] and ∆H was added in the NB main (I think) as part of the conversion to programme machine working in 1967. There are two TCs in the siding: P and M - the blockjoint being at the exit disc. I think that there is a ∆ in the siding in TC M nowadays.I think the undesignated links are off the power frame to the relays - this was the very end of the era when all the frame wiring could be shewn on one diagram Yes, Beta tracks are on the Vic; I asked about them yonks ago on the forum, then got a copy of Challis as mentioned upthread.
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Post by railtechnician on Aug 8, 2010 17:38:07 GMT
I'm not sure about the Pi Delta at Archway - but I'll look into it. EDIT: there wasn't a ∆ in the siding with the extension opening [unlike the Bakerloo takeover of the Stanmore branch a few months later, which *did* have ∆s] and ∆H was added in the NB main (I think) as part of the conversion to programme machine working in 1967. There are two TCs in the siding: P and M - the blockjoint being at the exit disc. I think that there is a ∆ in the siding in TC M nowadays.I think the undesignated links are off the power frame to the relays - this was the very end of the era when all the frame wiring could be shewn on one diagram Yes, Beta tracks are on the Vic; I asked about them yonks ago on the forum, then got a copy of Challis as mentioned upthread. I can't vouch for the PI Delta myself, I have never come across one AFAIK but the supervisor I referred to had once been a local lineman in the Camden Town area. I was a 'signal lineman' there just once for a single shift, in fact I wasn't a lineman at all then, I was a wireman (Tech 4E) with about one year or less on new works, it was a Monday night O/T shift and the lineman supposed to take the possession did not turn up so I was shown which fuse to pull by the supervisor and told to stand by the relay room until informed to replace the fuse. As the man who didn't turn up was an AET I was paid HGW at AET rate for the shift. If Challis is the maroon Vic line book I have a copy of that although I haven't looked at it recently. Technically I never really worked on Vic circuitry except when changing a couple of Picc relays in Finsbury Park IMR and back in my days as a Comms Chargehand working on a miscellaneous circuit involving a battery charger (a typical 12v car battery charger as I recall) in the escalator UMC after diverting a cable subsequent to the King's Cross Fire though I don't recall the details now.
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