2010 Cts in 2012 IRSE tables

[dorothy.pipet]

An attempt for comments - roughly took 1 hour and I didn't have time to go back and complete the controls associated with Flashing yellows.
I did find I got further in the time than with some other year's papers.

[PJW]

I think you did well as I think this was a tough year and many freaked at the layout- it take a long time to find way around it and using an A3 diagram at my age is a strain on the eyes to read the small text!

137
You have listed some routes which I think are superfluous:
463A(S), C(S)
474A(S) B(S)
don't actually pass over any 137 end, so these may as well stay Normal even though the train in passing diagonally along the ladder.

Conversely I think you have missed:
465B(M)
484C(M/W/C).

I see on your note sheet that you have assumed what I take to be 461C(M) to be via 137R and 142R; since it obviously cannot take an impossible turn at the switch diamonds, nor go via the reversing line (no trapping from the sidings and dept for a start) I actually can't see that there would be any alternative.


138
Can't see much wrong with this one-
1. For some reason you haven't put a time for release on EJ occupancy after 494
2. Also it seems that you wrote CM when you meant EM in the list of tracks after 463C(M) and put a bogus CM in the list of tracks after 465C(M). Either my eyes or exam pressure getting to you.

An attempt for comments - roughly took 1 hour and I didn't have time to go back and complete the controls associated with Flashing yellows.
I did find I got further in the time than with some other year's papers.

[PJW]

Returning to the routes:

Some general things as usual re
a) absence of notes for signal disengagement etc
b) overlap route locking
c) I think that doing Non-Permissive shunts is waste of your time

488B
Not many comments for the routes of the various classes, but

1. Given that 456 is 3 aspect signal on a 30km/hr line, then I think 488 would show Green up to it, not Double Yellow. Actually there is an argument to keep things consistent for the driver but that would make 456 a 4 aspect and that goes beyond what you can do.

2. If you (correctly) demand CG occupied to clear the signal, then total waste including CG in the comprehensive Approach Locking column as this lookback will by definition fail.

3. You didn't seem to have put 146 for the W route; having seen that you had put in the C route then I looked again and decided that it was in the W afterall, but I nearly put it down to a crossing out similar to the Reverse column in the M route- careful about that!

4. You should have explicitly written in the "or"s in the C route for
{(ES, ER-----or [(ES or ER) for 40]} expression because actually the expression you wrote actually evaluates to "Always FALSE" demanding the same tracks both clear and simultaneously occupied for the time.

5. Whereas you'd hardly want to put in all the modern overrun controls in detail, I do think that using the Special Controls column to list those signals protecting the route for which SPAD overrun detection would be included with this route's aspect would have been sensible.


473B

1. You demanded 146N but I don't really see why; however far more need to demand 144R! Its certainly arguable if this is appropriate, but you'd at least need (CJ or 144R) in the aspect for foul track.

2. You needed to at least set and lock 136N to give flank; it provides a "sneak" path that bypasses the protection that you think 137 are providing. In mechanical point-to-point, 136 would be "by (137 or 138)". 136N also prevents a concern about CL being foul.

3. You missed putting the A/L release time

4. Even if running out of time to include the MAY-FA in all its glory, you should not have made it look like you either
a) had completely forgotten / not noticed,
b) hadn't got a clue so were deliberately ignoring it
It looks like no approach release at all.

468C
1. It is arguable whether the route locking after 453B(S) is needed onto CM since this is locking 125N.

2. Seem to have missed the route locking from 455.

3. For the Permissive route you certainly don't want the route locking "as above" since the whole purpose of this route must been to signal onto a train stationary in platform 2 which could well have originally come from 455 or 453.

4. I know it was "according to the letter of the law of the standard" once but always seemed crazy to me that a shunt route given a longer overlap than a Warner- I definitely seem to recall reading somewhere that this situation had been rationalized in that where a ROL exists on a layout that any shunt route would utilise it rather than the full, but can't think where this was. I would have guessed the Signalling Principles Application Handbook, ut now that we have multipart Noticeboards being used to "amend" a whole range of standards and under the title "Simple is Effective" manages to very simply confuse the issue, I give up!



All in all a creditable attempt on what I think was a tough layout. Time would have better spent of the flashing aspect than the Non-Permissive shunt.
A bit more familiarity with the now somewhat unusual S&C formations still beloved of the IRSE- single and double slips, interlaced, switch diamonds, elbows etc would also be sensible exam prep.

An attempt for comments - roughly took 1 hour and I didn't have time to go back and complete the controls associated with Flashing yellows.
I did find I got further in the time than with some other year's papers.

[asrisaku]

Dear Dorothy and PJW

488B
one comment, do we need 127N, 148R, 137R?

thanks in advance.

regards, arnut

[dorothy.pipet]

In my opinion:
Calling 127N would prevent valid parallel moves between the departure and shunting lines;
148R would prevent valid parallel moves in and out of the spur;
Similarly calling 137R prevents moves along the down main to/from platform 3.

Obviously there is a balance required between setting every possible set of points to the most protective lie, and locking up the junction so parallel moves can't take place.

[StrongLifts5x5]

Hi Dorothy/Peter

I was looking at the feedback for 468C(S).

For 463D(S) route normal I was thinking EN,FN,FM,(FL clear or FL occ for time), my reasoning is a train might be shunted to 475 to be shunted back to platform 2.

Or is it OK to ignore FL track?

[dorothy.pipet]

Once a train taking an opposing move has passed the entrance signal for the route you're considering it's no longer opposing. It may be taking a "turnback move" such as you describe so we don't want to prevent the route setting.
In this case it means that once a train from 463S(D) has cleared FM track, 468C(S) should be able to set. No need to put any controls w.r.t. FL clear or occ.

[StrongLifts5x5]

Hi Dorothy yes that makes sense cheers.