Junction indicators

Discussion in 'Infrastructure & Stations' started by Scotty boy, 3 Nov 2011.

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  1. Scotty boy

    Scotty boy Member

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    Hi been a trainee driver for two weeks, bit confused about junction indicators i get that the feathers light up the indicated route to take. But in my signal book it states (Where the straight route is not the highest-speed route the junction indicator will apply to the lower-speed route) can someone explain this in layman terms i might be having a duh moment but not quite getting it
    Thanks Guys:lol:
     
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  3. Pumbaa

    Pumbaa Established Member

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    Surely you're best asking your instructor? There are many knowledgable folks on here, but also many, err, not quite so knowledgable in the field with which you require assistance.
     
  4. Scotty boy

    Scotty boy Member

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    Yeah im going to ask tomorow but thought id ask if anyone on here could shed some light
     
  5. Old Timer

    Old Timer Established Member

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    If you hang on a few minutes chap, at least one person will have the answer for you.
     
  6. 455driver

    455driver On Moderation

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    Is that the sound of pages being thumbed? :lol:

    Not by you OT.;)
     
  7. Tomnick

    Tomnick Established Member

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    Sounds like it's referring to a situation where the geographically 'straight' route has a lower speed than the 'diverging' route,in which case you'll get the feather for the 'straight' but lower speed route, and nothing for the higher speed route.
     
  8. GB

    GB Established Member

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    Pretty much what it says on the tin. As an example, if you had a junction where the main route bends off to the right and the other (lower speed route) goes straight on you would get no junction indication for the main (just your standard mainline aspect indication) and for the straight route you would get your main aspect but also a left hand route indication.
     
    Last edited: 3 Nov 2011
  9. Minilad

    Minilad Established Member

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    I always tend to think of it as the Junction indicator is for the slower or secondary routing. I am struggling to think of somewhere where I get a feather for a higher speed routing
     
  10. driver9000

    driver9000 Established Member

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    I assume by "signal book" you are referring to the S1 of the rulebook?

    Say you have a line that takes a Y shape.

    The left fork is say, 80mph and the right fork which is the straight route is 50mph. The feather will light for the 50mph divergance.

    That is the simplest way I can think to describe it.
    --- old post above --- --- new post below ---
    I can't think of one on any of my routes. The closest I can think of is an equal speed junction with a feather for both roads.
     
  11. Old Timer

    Old Timer Established Member

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    Aston South Jct ?
     
  12. Minilad

    Minilad Established Member

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    Feather is for a route towards Stechford. So no that is the slower / secondary routing
     
  13. Old Timer

    Old Timer Established Member

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    Yes but I think it is an example for the OP ?

    I dont think he was looking for examples of where there is a JI towards the higher speed route as this would be illogical. I cannot think of one I must admit. Is that what you meant or is it a typo ?
     
  14. rail-britain

    rail-britain Established Member

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    Pretty much but there are a few junctions where the expected main route is slower, as a result it receives a direction feather, and this is the section being referred to
    So lets sayyou are on the main line at 90mph, the main line straight ahead is 80mph, for example the line speed reduces due to an overbridge, but the line to the right is 90mph, the feather will indicate the main line to the left
    With no indicator the route to the right applies
    This is where route knowledge comes in
     
  15. Minilad

    Minilad Established Member

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    I read it as he was looking for a layman's answer so I suggested how I looked at it. I think we are on the same page though !
     
  16. Old Timer

    Old Timer Established Member

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    Of that I have absolutely no doubt, chap !
     
  17. 142094

    142094 Established Member

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    Micklefield might be one?
     
  18. Minilad

    Minilad Established Member

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    Not on my route card so couldn't say. Sorry
     
  19. 455driver

    455driver On Moderation

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    We all know that route knowledge is king because we all have sections of route that are the complete opposite to what would be accepted as "the norm".
     
  20. 142094

    142094 Established Member

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    Something is saying to me Micklefield but no idea why (line towards York and South Milford if anyone knows that bit of line).
     
  21. Tomnick

    Tomnick Established Member

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    From a quick search for images on Google, Micklefield appears to have a pos 1 indicator for the (physically diverging to the left) route towards York, and a pos 4 indicator for the straight-ahead route towards Selby. No idea of the exact speeds through there, but it's pretty fast onto either route.
     
  22. Schnellzug

    Schnellzug Established Member

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    On this subject, it always seems a bit counterintuitive, if that's the right word, but even if it isn't it's a good one, at Eastleigh, where from the both down platforms the feather is to go back onto the main line, while the 'straight on' is for the Fareham line, which seems (the start of it at any rate) a good bit slower.
     
  23. 142094

    142094 Established Member

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    Someone may correct me but I think the higher speed route is the York line.

    This may be something different to what the OP is talking about so happy to be corrected.
     
  24. Scotty boy

    Scotty boy Member

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    Thanks for all the replies. So if the feather lights for the 50 divergance. Does that indicate the route you are to take. Thanks
     
  25. Minilad

    Minilad Established Member

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    It indicates the route that has been set. But of course signallers can make mistakes too so it isn't always the route you should take !!
     
  26. Scotty boy

    Scotty boy Member

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    Ok so the route indicated is the route at a lower speed say 50mph. Does that mean that the route laid out for you is always at a lower speed.
     
  27. rail-britain

    rail-britain Established Member

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    From memory
    The line north (down) of Inverkeithing might have this setup, where the main line (towards Kirkcaldy) receives a feather
    Another is Stirling station Platform 6, the branch to Alloa is the direct route but the main line (towards Dunblane) has a feather
    --- old post above --- --- new post below ---
    In general yes, that is the meaning of the feather
    Again, local route knowledge is essential
    I suggest you ask your trainer if there are any local locations where this applies, they are very rare
    Equally, well spotted and bring this to their attention
     
    Last edited: 3 Nov 2011
  28. Old Timer

    Old Timer Established Member

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    Whilst it can be dangerous to talk of signalling principles, these days, the general convention is that a junction indicator is displayed for a route towards a lower speed line.

    The "normal" arrangements is that you will be travelling straight ahead on the highest speed route (the main line) and any junction to an adjoining line or to a route off the main line will always result in a junction indicator being received, simply because you have to slow down.

    The principal harks back to mechanical signalling where the signal for a route to a lower speed line was indicated by placing the signal arm at a lower level to the main signal.

    Because the junction Indicator, is normally (there are exceptions) released as the train approaches, there is the opportunity to stop at the signal and report an incorrect route if you are supposed to be travelling along the main line.

    I do hope I have not confused. If I have please say as this is important.
     
  29. pendolino

    pendolino Member

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    This example might help explain it. The signal on the end of the platform at Peckham Rye on the down South London can show a main aspect only, or a main aspect plus route indicator position 4.

    The line through the platform is on a right hand curve which continues beyond the station over Peckham Rye Jct onto the up Atlantic towards Denmark Hill. You would expect this to be signalled with main aspect only as (even though it's on a curve) this is the route that logically appears to continue straight ahead, but to continue onto the up Atlantic you actually need route indicator position 4.

    However, there is also another route (down Portsmouth) that diverges to the left at Peckham Rye Jct towards East Dulwich which, even though it logically appears to be a diverging route, is signalled with main aspect only.

    Why is there a route indicator for the 'straight ahead' route? Because the line speed over the junction 'straight ahead' towards Denmark Hill is 20mph, whereas linespeed for the diverging route to East Dulwich is 35mph.

    So you have:
    1. 'straight ahead' towards Denmark Hill - main aspect + route indicator position 4 - 20mph
    2. 'diverging left' towards East Dulwich - main aspect only - 35mph

    The 'straight ahead' route has a lower speed and is therefore signalled with a route indicator, which is what your quote from the Rule Book is telling you.

    I hope that makes sense. Good luck with the rest of your Rules. It won't necessarily become any less confusing. We've all been there: trying to understand what on earth the Rule Book is trying to say. But never be afraid to ask a question either of your instructor, or on here if you prefer the anonymity. There's no such thing as a stupid question when you're learning Rules.
     
  30. Scotty boy

    Scotty boy Member

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    It does make sense thanks old timer and everyone else who has replied. Im sure it wont be the last query i have thanks once again
     
  31. Minilad

    Minilad Established Member

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    I think a lot of this will become much clearer for you when you actually get out and about with a mentor driver and actually put it all into practise.
     
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