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Warner Aspects
#1
Hi,

I was going through the past papers of module 3. At a glance on warner route, the aspect sequence has just Y - > R.
I understand that when warner route is set and not stepped up, there can only be yellow aspect on the entrance signal with restricted approach release condition.

 When cross referenced with Network Rail standard 11201 A18(Erratum) & 8003 series standard, observed that the warner class routes are shown with full aspects just like the main signal aspects. Is it because the warner route steps up to main route and so full aspects are shown.

My doubt is how the principle tester tests the warner route if we show all the full aspects? if not stepped up, how can he check the other aspects, if we show all the  aspects that the signal has?

Thank You.
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#2
(19-01-2017, 06:09 PM)mailmesashi Wrote: Hi,

I was going through the past papers of module 3. At a glance on warner route, the aspect sequence has just Y - > R.
I understand that when warner route is set and not stepped up, there can only be yellow aspect on the entrance signal with restricted approach release condition.

 When cross referenced with Network Rail standard 11201 A18(Erratum) & 8003 series standard, observed that the warner class routes are shown with full aspects just like the main signal aspects. Is it because the warner route steps up to main route and so full aspects are shown.

My doubt is how the principle tester tests the warner route if we show all the full aspects? if not stepped up, how can he check the other aspects, if we show all the  aspects that the signal has?

Thank You.

You are right that for SSI and similar interlockings that the Warner route is configured to be able to show "better aspects" when the forward signal clears; the rationale is that if the warning route has already cleared then subsequent step-up to Main class route is not permitted.  This is a hangover from RRI where a brief reversion of the aspect would occur if we permitted the (W)RLR to drop out and then the (M)RLR to pick(as they are cress-locked against each other); I really do not see why step-up is prohibited in a CBI even after the signal has cleared.

So the Principles tester basically needs to set the warner, wait for it to clear, then set the forward route; they can then test the aspect sequence from the signal and can confirm that the warner route remains set by monitoring the relevant route memory.

However I do wonder why we bother; having displayed a delayed yellow since only a ROL available the train has nearly reached the signal and is travelling slowly.  What is really gained by allowing the display of an improved aspect in the last few seconds before the train passes that signal?  How often are circumstances such that the forward route happens to be set in the small time window that would exist between the signal clearing and the train passing it?
PJW
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