2006 Attempted Layout - Part 1

[alexgoei]

Hello PJW,

Appended please find my attempt on the 2006 Mainline layout.

Page 5 has a bit of comment truncated on the right side. This is with respect to the SSRB in which the + refers to "miles per hour. Higher speed for non-stopping trains".

Part 2 will contain the calculations, the notes and the route boxes.

Sorry for being so late in the day and requesting you to comment. If you cannot do so, I perfectly understand.

Thank you very much.

Cheers


Alex

[alexgoei]

Hello PJW,

Please find part 2 containing the calculations, the notes and the route boxes.

Thank you very much

Cheers

Alex

[PJW]

(26-09-2010 07:32 PM)alexgoei Wrote:  Hello PJW,

Sorry for being so late in the day and requesting you to comment. If you cannot do so, I perfectly understand.

Thank you very much.
Cheers
Alex

To be honest I am going to be struggling; certainly won't have the chance to do in the detail I have of the others. Perhaps I'll get the chance just to give a quick look at the layout and point out anything obvious. Depends on how things are at work this week; it has been expanding well outside its prescribed limits recently!

[alexgoei]

Hello PJW,

Yes go for the obvious please. But if you cannot find the time, give mine a miss. I'm OK.

Not that my attempt is superb but see this as a contribution to this Forum which has benefitted me so much. Hopefully others who attempt Module 2 in future will find them useful as learning points.

Thanks again for all your inputs and the amazing turnaround times!

Cheers

Alex

[PJW]

(27-09-2010 07:24 AM)alexgoei Wrote:  Hello PJW,

Yes go for the obvious please. But if you cannot find the time, give mine a miss. I'm OK.

Not that my attempt is superb but see this as a contribution to this Forum which has benefitted me so much. Hopefully others who attempt Module 2 in future will find them useful as learning points.

Thanks again for all your inputs and the amazing turnaround times!

Cheers

Alex

Indeed these are useful contributions to go with all the earlier ones on Control Tables.

1. Re the front cover notes.
I see that this has a hand annotation; it seems to jog a memory that the wording on the exam paper was queried. Can you let us know whether this was
a) your amendment as a candidate faced with coping with the printed text in the exam, or
b) whether this was a wording change advised to you somehow, or
c) already written on the version of the plan you were given?

2. GPL symbols
You have drawn all these as if PLs associated with a main signal, only having the off aspect. GPLs need to have an ON aspect as well! You are depicting the older 3 lamp version giving a red and white horzontally for ON and two whites diagonal (from bottom left to top right as seen by the driver stood at the signal) for OFF.

3. TCI symbols
Be careful to depict the two triangle "hourglass" to be attached to the "throw off" rail and not actually on the part of the pointwork which the trains traverse.

4. Description of runround mobements
I recognise that you did this before receiving feedback for your previous paper and therefore having a misunderstanding re what is meant by "standage".
However reading yoyr descriptions does illustrate various other issues:
a)Up Branch. Your description would be ok except for the fact that it starts with the assumption of the locomotive at the 503 end of the train. How can this be? There is no running move up to it- only 501 and therefore the loco must always be at the lefthand end!
b) CD Down direction. This is workable and sensibly described; if there had been a requirement to run around then this wwould have been ok
c) CD Up direction. This doesn't achieve a run around; the locomotive goes on a magical mystery tour but ends up exactly where it started. I suppose it gives the driver the opportunity to get a cup of tea from the station buffet!

What you did NOT describe was the one movement that you should have done: the turning of a steam locomotive via this triangle so that the smokebox end and cab / tender end are able to be interchanged without having to use a turntable. As it happens you have provided the signalling to alow this to happen so you'd get the credit for this; however my guess is that you hadn't actually provided for this move but only because of a mistaken understanding re the meaning of "standage"

[PJW]

(27-09-2010 08:31 AM)PJW Wrote:  

(27-09-2010 07:24 AM)alexgoei Wrote:  Hello PJW,

Yes go for the obvious please. But if you cannot find the time, give mine a miss. I'm OK.

Not that my attempt is superb but see this as a contribution to this Forum which has benefitted me so much. Hopefully others who attempt Module 2 in future will find them useful as learning points.

Thanks again for all your inputs and the amazing turnaround times!

Cheers

Alex

Indeed these are useful contributions to go with all the earlier ones on Control Tables.

1. Re the front cover notes.
I see that this has a hand annotation; it seems to jog a memory that the wording on the exam paper was queried. Can you let us know whether this was
a) your amendment as a candidate faced with coping with the printed text in the exam, or
b) whether this was a wording change advised to you somehow, or
c) already written on the version of the plan you were given?

2. GPL symbols
You have drawn all these as if PLs associated with a main signal, only having the off aspect. GPLs need to have an ON aspect as well! You are depicting the older 3 lamp version giving a red and white horzontally for ON and two whites diagonal (from bottom left to top right as seen by the driver stood at the signal) for OFF.

3. TCI symbols
Be careful to depict the two triangle "hourglass" to be attached to the "throw off" rail and not actually on the part of the pointwork which the trains traverse.

4. Description of runround movements
I recognise that you did this before receiving feedback for your previous paper and therefore having a misunderstanding re what is meant by "standage".
However reading yoyr descriptions does illustrate various other issues:
a)Up Branch. Your description would be ok except for the fact that it starts with the assumption of the locomotive at the 503 end of the train. How can this be? There is no running move up to it- only 501 and therefore the loco must always be at the lefthand end!
b) CD Down direction. This is generally workable and sensibly described; if there had been a requirement to run around then this wwould have been ok Only problem is that from 505to 507 is a very long way to be going in the wrong direction along a running line. There should definitely be an intermediate GPL at the EL/EK joint to protect 306 points at junction E- 505 is miles too far away. Also think of the length of time that the layout at junction E is being tied up for whilst this shunting movement at typically 10mph is taking place!
c) CD Up direction. I suppose that your description assumes that 108will clear to authorise movement to 502 LOS- however you have not provided any such route nor PL aspect on that signal so it is a non-starter. Even if that corrected, this procedure doesn't achieve a run around; the locomotive goes on a magical mystery tour but ends up exactly where it started. I suppose at least it would give the driver the opportunity to get a cup of tea from the station buffet!

What you did NOT describe was the one movement that you should have done: the turning of a steam locomotive via this triangle so that the smokebox end and cab / tender end are able to be interchanged without having to use a turntable. As it happens you have provided the signalling to alow this to happen so you'd get the credit for this; however my guess is that you hadn't actually provided for this move but only because of a mistaken understanding re the meaning of "standage" - a fortunate mistake I think!

5. Level Crossing
You staed an AHBC which I think could be a sensible choice but have actually seemed to have treated as an ABCL. They look quite similar to the road user but are fundamentally different from the rail perspective, so quite a lot of this is wrong. Also the strike-in points must be set to be 29 + 10 = 39 seconds running as it is a double traclk line and there is a need to build in a delay so that a 10 sec Minimum Road Open Time can be guaranteed should there be a train on one track shortly after operation of the crossing for a train on the other one. A t this time in the game not worth worrying about the finer details but need to identify the discrepency before it confuses others who may refer to this attempt in future.

6. Junction Signalling
a) The only 75km/h points are 306 & 308, so the only MAY-FA route is 208B(M). The route box for this route does not depict (but the plan does show the flashing Y and flashing YY for the signals in rear); the other signals where the route boxes show MAY-FA should be MAR.
b) Unless the berth track is only 100m long then the (S) routes for PL moves need not only a track occupied but the track occupied for a time- depends on the length of course but would be typically 15s. Similarly for (W) routes but the time may be a bit shorter assuming that ROL > 50m, so say 10s as a typical
c) 208B(M) should have PLJI pos 4 as I am sure you really know.
d) I think that 504 on your route boxes should read 509. If you need a route to the Up Main then you need to provide an LOS, I suggest opposite 209/211; as drawn the train can continue ad infinitum bang road along the running line which is certainly not good and eventually it will encounter an oncoming train with which it will crash. If providing such a route the MARI for that route should be "X"; if not providing it (is there any real need?) then I think that no MARI is required at all for signal 509.

7. Junction B
a) 502 needed for steam loco turning movement; therefore route to it needed from 108 (and possibly also 106)
b) Havingf provided 502, it may be that 501 is a luxury not really needed.
c) 106 looks to be foul; why not locate it further back from points? I agree that chord mmay be a sharp divergence, but if you are claiming it is at clearnce then mark the Clearance Point by CP and an arrow in situations where it looks tight, thus declaring your assumption, but do ensure that what you draw is feasible.

8. Chord
The English of the requirement re freight train standage isn't the best, but I think it really means one train at a time on either line and in either direction rather than two trains simultaneously on the chord, but I accept that it is ambiguous. a) If assume only one train, then move 108 and 112 furtherr back from junctions so that overlap within the chord. Abolish 105 (think you missed an equivalent signal in opposite direction).
b) If assume two trains then 105 should be 3 aspect instead of the distant board shortly beyond the 2 aspect; similarly for opposite direction.
c) Actually may be better off to make the chord permissive as seem to be no pasenger movements; so no intermediate signals but give both 203 and 103 a PL with MARI to read onto the chord line. (see 9 below)

The chord line speed is not defined so you should have stated a reasonable assumption; it is not that long, likely to be quite sharp curve so doubt if as much as 75 km/h may only be 40km/h. Certainly make it low enough that you can justify overlaps (which you are corect can be over points in the trapping position if we assume (did you state this anywhere?) that the line is only for freight. The overlap positions in the middle of 302 and 303 look to be foul- p[erhaps you meant to anotate these as being only applicable when the forward route from 108 / 112 has been set.

9. Junction D

I note that 203 hasn't been given a PLJI or route box entry, so can't signal onto it from Down Main at all; probably just careless slip!

Not sure if there is supposed to be IRJ between 304A and 303B; I think that it could all be one track circuit given the low utilisation of 505. Contrasts with junction B where it is sensible to split BG from BH as permits early reutilisation of the Down Branch once train has entered chord.

10. Junction E

This looks good.
I note that you have numbered the switch diamonds as 2 of a 3 ended point which is OK (but older practice than present day).

I'd have had 106 much further (ideally overlap clear if possible) from junction B, but then not had signal 110 I think (just looking at it briefly without actually seeing if fits with braking and headway). You don't absolutely need traps 305 as this is a running line, but with 110 as it is on your plan, it would make sense to have them in case the train rolled back when attemptng to start and would otherwie present unacceptable risk to traffic using junction E. Better though to get the freight to stop further from the junction and amalgamating 110 & 106 would ensure this.

You missed out an IRJ between 306B and 308; these need to be in separate track circuits to permit "parallel moves"- a train using 208B would otherwise drop DM and replace 107 to danger!

You don't need 503 (and indeed there is no route which reads to it); if however the layout were different and both 503 and 305 traps provided then np value in separating BM from BN track- just have as oneTC for economy.

507 LOS not needed- see earlier re runaround / standage.
A benefit would have been less track circuit sections in the tunnel. Even if 507 exists then don't provide a specific IRJ to be 180m beyond- save track equipment and instead combine EN and EP- who cares if the O/L is400-00m lonng since it is aLOS after all and there is no capacity disbenefit.


11. Station F

Good for providing the call-ons into the Down platforms in order to join the converging train portions from A and C together to permit continuance to H as a single train.

The ROL is a good idea but TOO SHORT; the absolute minimum is 46m and really would like to be at least 60m to stand a reasonable chnace of TPWS TSS being effective in a low speed SPAD scenario.

The 60m ROLs beyond 214 / 216 look tight- I think you are correct that they are not foul, since although they are within the convergence of the points the line spacing must be around 3m given the platform width- however you'd be wise to show the assumed CP just to emphasise that you had thought of it.

Well done for providing 212; it is obviously sensible for trains leaving the stabling sidings so this is the sort of thing that the examners are looking for to see if you are thinking operations.

Not sure why you provided 214 though; could look a bit of a luxury so suggest better not to provide unless you state an assumption that justifies provision.

You treated Up siding well- it wasn't mentioned for specifi use so you provided the basic route in and out. Even better was that you realised it needed 509 to be of real utility; as noted earlier I think provide no route from 509 to Up Main but if you feel one is justified then would need an LOS to which to read.

You drew 315 rails rather long so that couldn't really see which end was the trap throw-off- better not to have shown the line extending above and right but just have stopped the straight line.

It seems that the only O/L provided beyond 209 is DV/DW, but would want one that did not conflict with 211. I think that I would have defined a RPOL (reduced phantom overlap) at 314A.

The existance of 316 points certanly suggests that you are corect in providing a route to use them and this mustt be from 218 even though the layout notes don't explictly refer to an operational need. It is reasonable to infer a move into Down Loop (even if the Down Loop has only been given an arrow to the right not to the left as well); certainy allows access to the stabling sidings. Not convinced that 214 is justifed though (see above) so think I'd have only given a pos 4 PLJI reading to the loop and not had a route to the Down Main. However what you have shown could be sensible; so state an assumption that justifies why you chose to provide- you could always annotate with a # note and state "if required by client" for those facilites that might be useful but not absolutely required by the specification.

Sugest that should have provided a phone at the stabling sidings (or noted that 506/508 would be given SPT despite only being GPLs)

12. Station G

As mentioned earlier yyou got confused between ABCL and AHBC. Also although both only have barriers on the left of the road surface, there are road lights on both the nearside and offside. An AHBC doesn't have the flashing red/white DCI and tou'd need treadles to set crossing directionality each side of the short track across the road as well as treadles reinforcing the track operation at the strike-i points that should be at 39 sec running time, no SSRB signs etc.

Signals aren't interlocked but it isn't a bad idea to have them as you have drawn, but they would need cpntrols if they could condition out the strike in (seem to have provided as controlled but autos with emergency replacement may have been better.

Unless you need them their to achieve headway constraint, then don't need to provide platform starters at such a station- looks to me that you thought you did and have in consequence made the signal spacing rather odd because of this (but haven't thought through what you have done and why / better options)

[alexgoei]

Hello PJW,

Thank you very much.

You have certainly commented more than just the salient points!

Will go through them and if I do have further questions will clarify

Thanks again

Alex

[alexgoei]

Hello PJW,

Thank you once again for all your comments. I have gone through your comments and would like to clarify the following:

MAY-FA. The standard NR/SP/SIG/19609 Colourlight Junction Signalling suggests that MAY-FA is possible for a road with divergent speed of up to 40 km/h when the straight road is between 64 km/h to 120 km/h. I am aware that in Appendix S of the study pack that MAR is applicable when the speed of the divergence from the straight is above 16 km/h. So which to follow for the exams? I have extracted the relevant parts in this posting.

Hand written annotated comments. Yes those are mine as clearly it would appear that there was a typo of sorts under the operating requirements. Effectively that was how I assumed the movements to take place for passenger trains between H and C and trains from A joining and uncoupling at Station F.

Description of runaround movements. Some clarification is in order please. Standing of freight trains is required

[PJW]

(29-09-2010 05:18 PM)alexgoei Wrote:  Hello PJW,

Thank you once again for all your comments. I have gone through your comments and would like to clarify the following:

MAY-FA. The standard NR/SP/SIG/19609 Colourlight Junction Signalling suggests that MAY-FA is possible for a road with divergent speed of up to 40 km/h when the straight road is between 64 km/h to 120 km/h.

Standard refers to 40 mph=MILES PER HOUR,
not 40km/h which equates to approximately 25mph

Quote:Hand written annotated comments. Yes those are mine as clearly it would appear that there was a typo of sorts under the operating requirements. Effectively that was how I assumed the movements to take place for passenger trains between H and C and trains from A joining and uncoupling at Station F.

Yes just the sort of thing you should do under those circumstances.

[quote]

Description of runaround movements. Some clarification is in order please. Standing of freight trains is required

[alexgoei]

Hello PJW,

Thank you for the reply

Sorry to belabour the issue concerning MAY-FA but the second row does mention permissible approach speed of 40 - 75 mph (64 - 120 km/h) and divergence speed of 25 mph (40 km/h).

Cheers

Alex