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2001 Layout Route CT's
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If anybody would care to comment it is appreciated.
Thanks Ian Note these were done Prior to PJWs comments re the route CT 2002 layout so lessons learned not applied just yet
22-07-2010, 06:25 PM
Hi,
I have just looked in to the routes and found the below points. For Route 113A(M): 113A(W) require locking where 209A(W) is shown by mistake. 209 is the point in the route. 109A© should be locked with track circuits clear as per Huddersfield locking. You missed out track circuit 'BP' which is in the route in Track Circuit clear column. The same is the case in the TC sequence. It should be AN clear, BP Occ after AN occ, BP occ. For Route 113A(W): Instead of 113A(M), 209A(M) is shown. 109A© require locking with TC clear. Missed BP track circuit and the track sequence. For Route 305B(S): In the Opposing locking, Route 108B(M) and B(W) does not require BH Track clear as it is the Berthing Track for signal 305. The aspect displayed column should be PL alone as the exit is a shunt signal which will not have a Red aspect. Please correct me if am wrong. Thanks in Advance. Regards, Jenni. 
24-07-2010, 10:27 PM
(22-07-2010, 11:47 AM)merlin89 Wrote: Points added Note that in the actual exam, the question asked for points 203 and 207. It is excellent to do extra ones when practicing; not a good idea in the exam itself! Blank CT I think the blank works well bit I think that the Set by routes could have been 3 wide rather than 4 and the extra width better allocated to the sectional route locking tracks clear column. Also think that the Time of Operation locking takes up space and is rarely needed; hence I'd have used this space within the CALLED R to N and just have written in long hand if it happened to be neede in the Notes. Most unlikely to get 2 points both with T of Op in the same exam so no saving of time by photocopying the blank on this bit. Also feel it is reasonableto put the point numnber above the grid frame after the question number entry in the centre of the page at the top, written large. 203 You missed the flank to the Up Fast: 102A(M), 108A(M), 110A(M) that I would hae expected. For 303 A(S) and B(S), I think you forgot which points you were doing because you show EB and EB DB; similarly 301B(S) and C(S) 207 You missed the A routes from 108, 110. I always think it is a good idea that once you have found a signal which calls points a) to look at the route box for that signal and check each and every route- whether it should call N, call R, or not call at all. Doesn't take long and helps prevent you missing one, particularly if M/W/C etc b) check every parallel signal in case there are routes from these as well which also should call the points; another cross-check It does depend a bit on the technology of the interlocking but best that where there is locking on points within an overlap then the occupied track should only bypass the locking on that track and any other which may feasibly be occupied by the train when stationary. A train waiting at 109 would have cleared AG so this locking should be "outside the bracket". A train waiting at 108 could well be on BM and BN, but not on BP I think, so BP should be "outside the bracket". You have included within the sectional locking entries the overlap tracks- you don't need the one which deadlocks the points but you are correct that the other(s) should be listed. So route locking after 107A(M) should have been AJ, AG [AH ---or AH occ for 30s] Actually I think the time is abit short for a 400m track, but it is of the right order of magnitude so don't worry too much about that. Similarly I am only picking you up on detail of the overlap locking presentation because the rest of the CT is ok; the really important thing is that the locking is shown, the precise detail is a bit of a nicety. You included too many tracks after routes 310A(S) and B(S); a good tip is always to compare the last track with the one you wrote in the dead-locking column- be very suspicious if they don't match. Obviously for a crossover being locked normal the route locking will only feature one or other of the dead tracks, whereas for a crossover reverse it will list both. Also useful when there is a foul track or a conditionally foul track; acts as a cross-check that you have written it correctly. 206 You missed 305 A/B/C(S) for some reason; thi was a shame when you had caught those routes reading over 205 Reverse as needing to call 206 Normal, firstly to get a bit of flank and secondly to avoid locking 206 the wrong way by DE and thus preventing use of the Up Fast for no good reason. You attemptd to show some swinging overlap, counter-conditional locking. You very nearly got it right; the only problem being that there isn't any! The first hinge is 205 and 206 is the second hinge beyond 111. Thus as far as 206 are concerned, in either of its overlaps then 205 must already be Normal and it is a simple swinging overlap with track DE in both of them and BJ as the additional track when 206R; however BJ deadlocks 206 and therefore there is no need for any additional locking. If you had been doing 205's CT instead: then for 205 to go R at a time when 206 was R (assuming that this is a feasible status- i.e. not prevented by point-to-point) then 205 would need [(BJ or 205N) or routes to 111 normal] and this indeed would have been presented in very much the manner you used. It is pretty unusual for a point to have counter-conditions both N to R and R to N so be a little suspicious of writing that; however it does occur, but for obvious reasons the actual conditions will be slightly different and so at first glance (before looking at the layout) your presentation looked perfectly feasible.
PJW
(22-07-2010, 06:25 PM)jenni.joseph9 Wrote: Hi, I was rather surprised re the number of routes and therefore checked back to the question paper: certainly it says 107B, 113, 305B so the examiners seemed to have been kind that year in terms of quantity; no doubt they were hoping that quality would be improved as a result. In fact it does seem quite an easy layout compared to many others. Blank CT I think this works ok, although I'd be tempted to make the route calling level a little deeper; you could probably sacrifice two divisions from the Aspect Displayed row. If you get a route with lots of opposing route locking then that extra space at the top level would be invaluable. I suppose it would be a bit messy and time consuming but if you typex-ed over the division marks that you are not utilising on the top border line, you could then save some space at the top by writing your text higher up where these currently are. Otherwise I suppose you could always use the Notes are at the bottom as an overflow which you could arrow up to the relevant area. You are probably wise to list the individual point ends that are detected for the time/space that it takes to do so; hence you don't need to write "all ends" in the box heading- this will save you a little space in what is squashed. I'd loose the vertical divisions which you have shown within the Comprehensive A/L presentation- the first isn't needed at all and I think you can forgo the second (under "or" as there will be enough separation to be clear) and thus you are left with the 3 methods which column heading shows. Route 107B(M) This was pretty good including the swinging overlap. I think that I might wondered about setting 206N for the overlap over 205R, but that is a frill. Again I wouldn't have written the aspect level re the point conditions in the swinging overlap quite like that (I'd have had combined entry spanning the first 3 columns linked by dashes), but the presentation was clear and, apart from quibbles, correct so stick with it. You showed G up to 111@G; nothing wrong with this but not supported by the route box supplied. Since the only route for which 111 can show Green is into platform 1, then it is not going to be a usual move at all as 107A would be used instead. In the mindset of RRI then the "better aspect" would not have been provided because it cost to provide it; in the mind set of SSI it comes for free (and indeed would be more trouble to prevent it!). Hence I agree with your CT (you didn't define anywhere your standards but I am sure that you are "SSI minded" and the separate A.L for each class of route from a signal reinforces that)- however that is just the thing to note in the remarks column to show it is conscious decision, not a failure to read the route box information. Comprehensive A/L lookback. Since 107B(M) cannot clear unless AF occupied, then this route would be "when cleared". The entry you showed would however be appropriate for 107A(M). Route 305B(S) You missed some opposing locking from 310B(S) and 110A(M) for some reason; I suspect that you did 108 and then looked further to the right and got yourself sidetracked. Always worth reviewing the entries when you think you have them all and then just looking for the "parallel" signals to any that you have listed, just to make sure that you have excluded them for good reason, not as oversight. Jenni is correct when says: In the Opposing locking, Route 108B(M) and B(W) does not require BH Track clear as it is the Berthing Track for signal 305 the route locking after 108 etc should be only to BJ, not BH Simiarly Jenni is correct when says: The aspect displayed column should be PL alone as the exit is a shunt signal which will not have a Red aspect Aspect is just PL; it is a GPL not a (S) associated with a main signal! Quote:Route 113A(M): Indeed I think you must have had a brainstorm and wrote 209 ather than 113; also you meant 312B(S) rather than 312A(S). The route boxes for the Up have been done in an Eastern Region (=upside down) manner that us Southerners just think is done to confuse.......Keep your wits about you in the exam. Yes to modern standard all routes from the platform exit signal would be locked whilst there was a call-on (or sometimes also a shunt) route in progress from the platform admission signal. I'd represent this is a simplified form as: Route Normal Maintained by Tracks 109A(C ) AJ, AK 111A(C ) DE, BJ, BK, AK 305A(S ) BJ, BK, AK The requirement is so that drivers receiving a permissive passenger PL aspect don't get used to finding the platform clear by the time they arrive and therefore exercise insufficient caution, until one day they find that they do need to stop their train short of the previous train. If the locking is being provided for a call-on, then many places also impose it foe shunts as well for consistency even though not strictly needed. Yes you fell for it; ALWAYS look for the track joints and then find the relevant track name; don't just look out for the track names your route passes over. If you were really clever you might decide that BP over 209R was such a short track that may not be seen as occupied for 2 seconds which could mena that SSI wuldn't achieve TISP; the solution wuld be to use BP and BQ in combination as the "2nd" track in the A/L release. The other thing that you missed because it was not there is the opposing route locking up to 118. The oplan is deliberately silent regarding what happens at the far end of the single line, but you can't afford to adopt a "out of sight, out of mind" approach. You should have recognised that there would need to be some way of avoiding a head-on collision. There is no reference to working line by token, there is no obvious slot but it appears to be a line worked by TCB. Put a note in the remarks column and postulate a signal 122 and give it route locking on tracks BW, BV, BU, BT, BS. You noticed the requirement for signal 115 to be off- you probably didn't need your #1 note as the CT reflects anyway, but does no harm Quote: Yes same issues again. I do wonder why gave you two such similar routes. You could have mentioned that (W) set by use of separate exit button. I think that 10s trather short for A/R; I'd have gone for more like 20s You show that signal only shows best aspect as Y; this time you followed the Route Box whereas SSI practice would have permitted it to show G if signal 115 changedafter 113 had cleared. It doesn't really matter what you do in such circumstances, but try to be consistent
PJW
14-09-2010, 08:44 PM
Peter
I seem to be having a few issue re my lengths of TC from the layouts and as such is hampering my ability to grasp the principle of which time to use fromyour time values doc. for example the OL for 113A(W) is 50m which is less than the minumum of 55 ( however is marked up as O/L and not ROL) so Im assuming a time value of 0sec; the issue with the layouts is I cannot guage how long a track is e.g. tracks AL or Am at Platform 1 or even tracks BM and BN at platform 2 how can you figure out their lengths for timing of overlaps. Same goes for Approach release track ccts. Can you help please? Kind regards Ian (14-09-2010, 08:44 PM)merlin89 Wrote: PeterFirstly don't worry too much about precise time values; just aim to get an approx value: 5 sec, 15 sec, 30 sec, 60 sec etc. Sometimes it is a guess but use what you know or can assume: signal spacings are often given, overlaps are probably 180m, train lengths are often given - from which lengths of plaformas can be inferred (e.g if there is a call-on PL then platform may well be twice the train length). The minimum ROL is 50yds = 45m. As a generala rule of thumb I say that a signal for a (W) should clear when the train is as far from it as the length of the ROL beyond the next signal, timing for a few seconds is sensible even with a 100m berth TC. AL+ AM = 542 - 220 so we actually know the combined length exactly, but I'd just take to be 300m AH = 600 - 180 so it is clearly just over 400m
PJW
15-09-2010, 11:33 PM
thanks for that Peter but Im afraid Im not getting the timing for the warner for 113.
as I see it the O/L is 50 m minmum length therefore must be timed nearly to a stand and we use the berth track circuit length , the route box says Am occ for time . AL+AM= approx 300m So to fit a MU at 100m and a loco at 200m would I be right in guessing AM = 100m so the time to stand would be 10s? (15-09-2010, 11:33 PM)merlin89 Wrote: thanks for that Peter but Im afraid Im not getting the timing for the warner for 113. I agree that both AM and also that portion of AL alongside the platform are just over 100m long so that two multiple units or one loco hauled train can be platformed. The ROL is short so the "practically at a stand" values as also applicable to PL release are appropriate. Therefore 10sec is correct. Using my other rule of thumb to get a sense check using that figure, the release should occur at 50m from the signal. This would mean that the train wil have therefore been on AM for 10 sec and thus have travelled 50m in 10 sec, so 5 m/s which is approximately 10 mph. This averages the final approach speed so as we can be expecting the train still decelerating, it is clear that the instantaneous speed when the signal clears will be lower than that- it therefore is very close to being stopped.
PJW
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