2006 Attempted Layout - Part 1

[PJW]

(30-09-2010 05:39 AM)alexgoei Wrote:  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

So it does- my apologies.

Standards change and one ends up not knowing what one thought one knew. In reality I think that recent change has been made particularly for getting a freight train off the main line into a Goods Loop faster, but yes it does seem that your solution is compliant and I was wrong. One advantage of having to learn from scratch is that you read what is written, rather than being pre-conditioned by previous knowledge and experience. I certainly haven't encountered a flashing aspect in such a scenario, but perhaps this will become the way of the world. In my defence I think that if you look at the compliance clause of the instruction published in September 2006 that it would NOT have been applicable for a layout signalled at the very beginning of October 2006 (joke!)

One problem that you have to face is the examiners might take exactly the view I did, but without the opportunity to discuss afterwards. The mindset of presenting a candidate a layout with certain turnout speeds higher than most others certainly suggests that they are expecting the signalling to be different........... I think I'd still advise caution over what may be seen as the overuse of flashing aspects. [There are risks associated with MAR and risks associated with MAY-FA which are hard to balance; I believe that one of the motivations for NR to amend its standards has in fact been commercial pressure from the train Operating Companies- compare the wording agasinst that of the older Railway Group Standard that is still in force].

I think where the turnout speed is as low as 25mph which as you note is the minimum permissible speed, you really need to consider whether you would provide MAY-FA. Whereas it may be compliant to do so that doesn't actually mean that it is appropriate. I think in that case I wouldn't depict it on the plan but add a note that it could be an option. If you provide in such circumstances then probably worth a note that it is compliant and quote the standard number, so the examiner is perhaps jogged into looking it up rather than relying on their experience!

[alexgoei]

Hello PJW,

I see some advantages of showing both if they do occur in the exams. One demonstrates to the examiner one can produce two types of junction signalling.

Thanks

Cheers

Alex

[PJW]

(01-10-2010 01:55 AM)alexgoei Wrote:  Hello PJW,

I see some advantages of showing both if they do occur in the exams. One demonstrates to the examiner one can produce two types of junction signalling.

Thanks

Cheers

Alex

Absolutely. However what I am saying is that if you have already shown MAY-FA for the juncyions having whatever the "high" speed is on that layout, then show MAR for all the "default speed" turnouts