Initial exercise

[PJW]

Sorry my mistake! I hadn't noticed the attachment format had been rejected.

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PS: Ommission-All the aspects in the shunt routes are position light.

I note that you hadn't read comments on previous attempt when submitting but I assume you have now done so; hence will not repeat myself needlessly- "if the cap fits, wear it" and learn from other's mistakes as well.

Again only the person making the attempt will really know what was a silly slip-up and what was as a result of not fully understanding, but I can make an educated guess.

1. You appear to have misread the diagram as to which signal is MA63. True not very clear but should be able to tell, particularly as there is a pattern to the numbering (even on the up, odd on the down); indeed you have not even been consistent, so can't have it both ways!

2. 67A(M) you stated points 104N; you need to watch it- the straight lie is not always Normal. Note that you also put 104N for 67B routes so again you should have tumbled to the fact that one or other must be wrong.

3. You have also stated 67A(M) approach released- but it is the straight route and has no route indicator, so why? If you really thought is was then you should have given more detail re the track conditions for the approach release. Conversely you have not stated that either 67B(M) nor 67B© was approach released. Since the divergence is 25mph from a straight line speed of 50mph then the differential is >10mph and therefore approach release needed. There is no hint how long track CV is and we also need to make assumption re the PLJI sighting so can't really be sure, but let's say "CV occ for 20sec". The PL move just has to be severely approach released to ensure that train "nearly at a stand", so let us put "CV occ for 40sec"; the actual values don't matter but the fact that they are potentially sensible values and differ from each other in a sensible way is what is important.

4. You stated that 67B© is a permissive move; if we grant that you believe that the train from the south is propelled back onto the UP loop from MA200 and the locomotive then needs to be signalled via 71A(S), 200B(S), 202A(S)68A(M), 67B© then obviously it must be permissive as DA would be occupied by the remainder of its train. However you have stated that the aspect should prove DA clear; the whole issue is that a permissive route would NOT prove all tracks clear- for a shunt you

[peternrz]

I am submitting a corrected answer.

Please explain meaning of " run round" as per Note 6 on the layout.Also,if MA200B(S) requires MA202 off as per Note 6 on the same layout; does MA202 remain the exit signal for this route?

[PJW]

I am submitting a corrected answer.

Please explain meaning of " run round" as per Note 6 on the layout.

Locomotive pulls vehicles along the branch from the colliery in the down direction and hence on the righthand end as seen in diagram. It stops at 71 signal, uncouples and leaves them in the Up Loop. The run round move is for the locomotive now to get to the other ens of its train, in this case it has to cross to Down Main via 101R, get behind 200, then via 202, 68 to get behind 67 and then needs the PL aspect to make a permissive move back onto its train. Loco is now at left hand end and could pull the wagons in the up direction. In this example there is no suitable connection so it actually needs to set-back its entire train propelling wagons onto the Up Main. Not highly desireable and such moves towards LOS should be of the shortest practicable distance.

You do need to understand train operations in order to signal the layout in mod 2 or do Control Tables in mod3!

Also,if MA200B(S) requires MA202 off as per Note 6 on the same layout; does MA202 remain the exit signal for this route?

Indeed MA202 is the exit of MA200B(S). However the ASPECT will remain at red until such time as MA202 shows proceed. A driver will probably not expect to stop at MA202 as in their mind they are undertaking a "run round"; being just a GPL there is a potential SPAD risk. This is avoided by holding the loco at MA200 until the driver's potential expectation can be made reality. On certain layouts it might be operational essential to free up the layout (and tus such a control would be omitted but perhaps with some other partial mitigation) but on this one there is not a great deal of benefit in allowing the loco to drop down to MA202 as not in the way of anything else whilst waiting at MA200- hence better to be that little bit safer by imposing the control specified.

On a mod 3 layout you may care to put such a control in because you feel that your railway's practice would do so; however if the control is actually stated in text or a route box then you MUST put it in (or at least explain that it is NOT a practice appropriate to the railway on whose standards you are basing your answer)