2012 Module 2 Layout

[abcd]

Hi,
I have attempted 2012 Module 2 layout. Please advice the tips for improvement.

[PJW]

Hi,
I have attempted 2012 Module 2 layout. Please advice the tips for improvement.

Some brief notes; I am only looking at the layout on a laptop screen when in a hotel, so not able to give a full review as can only see bits of the layout at any time:

• Freight Terminal- the thing you thought was a User Worked Crossing is actually a set of gates within the fence around the terminal through which the rail track enters.  Even if you didn't recognise the symbol, had you read the Operating Requirements Notes carefully [AND YOU ALWAYS SHOULD] then it should have become evident.
  
• You should have had short explanation re means of signalling beyond the boundary of TCB; not sure what is the control methodology on the single line.  Are you proposing a train staff for the line A-B so that there can only be the one train?
  
• The boundary is also drawn in a bit of a funny place. I am unclear where the exit signal of the route from 135 is (because the limit of TCB would be where that signal / STOP board were placed); you could have placed it opposite 201B for the train to stop at prior to the locomotive running around.
  
• You have signalled the runround ok (apart from the GPL symbol not quite right), but have no means of signalling into or out of the little siding at the left hand end (which could also do with a bufferstop light)
  
• Suggest 102 (if placed there at all) should have been a little further to the left so can get the whole train out of the terminal so that the gates can be shut across the line behind it; otherwise perhaps combine with 302 (although in that case obviously the rear of the train will foul the gates)
  
• Placing 104 opposite the end of the station B platforms means that overlap extends over 205; it would have been better placed so that its overlap was clear of them so a freight could be brought up to that signal whilst passenger train arriving/ departing in order to aid in slotting the freight train in a path between two consecutive passenger trains
  
• Branch is somewhat oversignalled; I think isolated 3 aspect signalling (i.e. Red/Green with Yellow /Greens on their approach) would have sufficed for most of it (but spacings look such that some 3 aspect signals would probably result).  Signal 108 is not needed at all.  Signal 127 doesn't need a Red but just be a distant; similarly signal 110, 116, 127 etc.
  
• From a layout perspective, signal 118 would be better some 200m closer to station E.  Agreed there is the braking constraint to observe, so I would have placed at minimum braking from 120.  Actually I would be pempted to propose a 40km/h speed restriction over that final portion of the branch so that I could not only have got the signal closer, but also not have needed approach release for its other main routes.
  
• You have not drawn the switch diamonds correctly, although the numbering of the ends as 207A and B is fine.  They do not have curved thin switch blades but very much more stubby and robustly tapered ends, so on the plan they are shown as stubs and also a diamond symbol drawn within the acute angle.  Do look at the IRSE's layouts for the mod3 Control Tables and all the symbols utilised and then get them right; your GPLs, PLs on main signals etc. are all a little "off".
  
• Similarly take note of the Clearance Points; you have drawn those at 206, 210 etc in just the same way as other points, but the issue is that they are difference as the lines are clearly widely spaced here due to the platform.  Signalling Plans are not to scale laterally- you need to use the clues to interpret them.  Probably just a simple oversight, but I notice a track joint missing between 208 and 207.
  
• Looking now at the mainline from D, the first question is where is the signal protecting the throat pointwork for station E?  A bad omission.  OK signal 122 needs to go where you have placed it and the speed of the line is such that braking distance is long, but you can't just not have a signal!  Clearly this was one of the challenges of this paper; you were dong pretty well up to now but you flunked this one!
  
• You have given signal 121 a SARI with two indications; should have been a signal with a PLJI pos4 for the divergence on to the branch because the straight speed is high.  Similarly signal 122.
  
• You have not given any signalled move into the Up siding.  The notes required arrival & departure in ANY DIRECTION (i.e. all the possible places it could need to go) which suggests you need to look at what extra GPLs you may need around that area of the layout to facilitate; however you didn't even give it access from the Up Main!
  
• Signal 115 is longitudinally sensibly positioned for Up trains on the Down Fast; however it does not look to me that there is space for a straight post between the tracks so you'd need to cantilever it from the cess or have a gantry.  The bigger problem is that you have no equivalent signal for the Up Main; don't think just because you have filled the area with a route box that the examiner won't notice the omission!  The other thing is that although positioning is sensible, it is far too close for a yellow to be braking distance from the platform starting signals, but you have not given your solution to that problem.
  
• You have provided what I believe is a 4-car length marker on the Down Slow; it's ok but I am not convinced it is needed.
  
• Between stations E & F you seem to be placing 3 aspect signals at approx 800m; how does this align with your braking distance calculations?  The Down Fast spacing is conversely 1700m.
  
• I did notice that you had put an "isolated 4 aspect" signal 111 on the Down Fast, but don't understand what you think it is doing for you.  Indeed it is actually drawn as a Y/G/Y signal but given that the next signal is 1700m beyond it, I don't comprehend what you were trying to achieve.
  
• You were correct to put a ROL beyond signal 132, but you should have shown the associated Warning route from the signal in rear.  The signal does not need approach control because it only has one route and the driver has to be familiar with the speed of the line by virtue of him having signed for having relevant "route knowledge".  The comment you wrote re the rationale was not correct- actually I believe that it is only the 213 crossover which is 100km/h, not the single lead 214, though I must admit it is not completely unambiguous and it is the sort of thing that a candidate should state as an assumption- wince the Down Slow is itself 100km/h there would certainly be a rationale for 214 also to be 100km/h
  
• I can see now clear requirement for providing GPL 301 at station G; however I would agree, seeing the Down Main is reversibly signalled, that it could be quite useful.  In such circumstances I'd recommend a note to explain what use you foresee for it; effectively make it an "added option that the client might wish to consider".
  

This actually has become a longer list than I initially expected.  You will also realise that there are some bad mistakes listed above.  However there was a lot of the layout which was quite reasonable; I have seen very much worse,  You have avoided many of the silly things re trap points, track joints etc. and so you would have been picking up quite a lot of marks.  It was primarily your signal spacing and aspect sequence which let you down; you do need a better understanding of when to use what type of signalling, how to transition and what to do when signals can't be spaced braking distance apart.
Having said that, if you did the layout in exam conditions as fully and as well as this as well as doing the braking and at least the non-stop headway calculations, I think you would probably have passed.  Remember you only have to get 50%, so even a layout that is not particularly good will pass provided you can demonstrate to the examiners that you broadly understand what you are doing.