https://irse.signalpost.org/ Wed, 22 Apr 2026 13:41:36 +0000 MyBB https://irse.signalpost.org/showthread.php?tid=1806 Tue, 26 Aug 2014 19:15:26 +0000 PJW]]> https://irse.signalpost.org/showthread.php?tid=1806
Actually this was an unusual layout since the through station has a severe speed restriction through it and therefore even non-stopping trains have to slow down and therefore stopping headway type calculations dominate. Also the headway requirement combined with the slow speed means that closely spaced signals are needed.

These calculations are not the easiest to follow but broadly along the right lines. Certainly they would have taken far too long in exam conditions, so a "quicker and dirtier" approach is probably called for.

Many candidates tend to ignore stopping calcs completely since believe there are easier marks to gain elsewhere in the paper, but the examiners occasionally "retaliate" by coming up with a layout that really needs them. It is one thing to decide within the exam that your time is better spent on doing something else, but it unwise to completely ignore during your pre-exam preparations because you run the risk of being presented with a layout for which they are unavoidable and then you would then be insufficiently prepared. Definitely worth thinking prior what you'd do when faced with such a layout!]]>
Actually this was an unusual layout since the through station has a severe speed restriction through it and therefore even non-stopping trains have to slow down and therefore stopping headway type calculations dominate. Also the headway requirement combined with the slow speed means that closely spaced signals are needed.

These calculations are not the easiest to follow but broadly along the right lines. Certainly they would have taken far too long in exam conditions, so a "quicker and dirtier" approach is probably called for.

Many candidates tend to ignore stopping calcs completely since believe there are easier marks to gain elsewhere in the paper, but the examiners occasionally "retaliate" by coming up with a layout that really needs them. It is one thing to decide within the exam that your time is better spent on doing something else, but it unwise to completely ignore during your pre-exam preparations because you run the risk of being presented with a layout for which they are unavoidable and then you would then be insufficiently prepared. Definitely worth thinking prior what you'd do when faced with such a layout!]]> https://irse.signalpost.org/showthread.php?tid=257 Thu, 16 Jul 2009 14:11:49 +0000 CMcGrory9]]> https://irse.signalpost.org/showthread.php?tid=257 Before I start asking any silly questions i'll offer up my attempts at the '98 Stopping Calcs. I was comparing my answers to those on they Model answer provided with the Study Pack.

I think I found from my scribbles that 3 Aspects was not only sufficient but even slightly generous given that Signal Spacing can be at Braking+33% and still easily acheive the Headway Time including with 20% deducted for contingency.

The model answer seems to have calculated that HD = Length + O/lap + Sighting + ONLY 1BRAKING. Consequently the calculated Hd appears to be far too short.

Is this a genuine error or:
Have I missed something very rudimentary and obvious and not considered it?

Is this intentional by IRSE to demonstrate that you can get the maths wrong and still succeed with good knowledge - The layout is well signalled (as far as i can tell) because a very large station dwell time has been added by the candidate which has covered the earlier error and hence the layout achieves the stated aims of the operators?

Any comments are appreciated - I can upload the 98 model answer page for anyone who doesn't have access to it.]]> Before I start asking any silly questions i'll offer up my attempts at the '98 Stopping Calcs. I was comparing my answers to those on they Model answer provided with the Study Pack.

I think I found from my scribbles that 3 Aspects was not only sufficient but even slightly generous given that Signal Spacing can be at Braking+33% and still easily acheive the Headway Time including with 20% deducted for contingency.

The model answer seems to have calculated that HD = Length + O/lap + Sighting + ONLY 1BRAKING. Consequently the calculated Hd appears to be far too short.

Is this a genuine error or:
Have I missed something very rudimentary and obvious and not considered it?

Is this intentional by IRSE to demonstrate that you can get the maths wrong and still succeed with good knowledge - The layout is well signalled (as far as i can tell) because a very large station dwell time has been added by the candidate which has covered the earlier error and hence the layout achieves the stated aims of the operators?

Any comments are appreciated - I can upload the 98 model answer page for anyone who doesn't have access to it.]]>