Bus & Tram controlled traffic lights

Discussion in 'Other Public Transport' started by sleepy_hollow, 15 Mar 2019 at 12:33.

  1. sleepy_hollow

    sleepy_hollow Member

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    I would welcome references to bus or tram controlled traffic lights, both system (1) and equipment level, particularly manufacturer's data or official descriptions of systems, although histories would also be useful (2).

    I am thinking of things like refs (1) and (2) but for as many examples as possible, both in the UK and abroad.

    It is my understanding that trams have always controlled road signals, but that buses doing so is a newer development. Also I believe that trams often, but not always, have absolute priority in setting signals for the tram route. I suspect UK practice tends to regard a tram route as something that should take its turn with other traffic, as bus routes generally do.



    (1) Selective vehicle detection in London – official TFL leaflet http://www.tfl.gov.uk/assets/downloads/businessandpartners/svd-brochure-2006.pdf

    (2) Bus & tram priority in Sheffield – unofficial description
    http://busmeister.wikispaces.com/intro_TSP
     
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  3. kilonewton

    kilonewton Member

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  4. rebmcr

    rebmcr Established Member

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    I know that when the T68s were introduced in Manchester, detection was by two induction loops buried between the rails, set distances from the stop position. On smaller junctions they had absolute priority, but in some of the more important locations (e.g. Princess Street) they only had relative priority within the usual cycle.
     
  5. sleepy_hollow

    sleepy_hollow Member

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    Thanks for both comments.

    The Melbourne paper definitely describes what I was thinking about, although as far from the UK as you can get. I assume that it is not necessary to go to the antipodes to find this sort of thing although an academic paper being dated 2018 does suggest that the idea still has some novelty. Interesting that it is based on conventional induction loop technology.

    Equally interesting that tram control of road traffic signals in Manchester dates only from 1992, I had thought trams had controlled signals from the beginning of electric tramways, but I suppose traction motor current control of points came in before traffic lights.

    As you might expect the Manchester Metrolink website provides little technical information.
     
  6. rebmcr

    rebmcr Established Member

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    I can't speak to that — it may well have existed also on the previous tram system, but that pre-dates me!

    I seem to recall the information I posted originally came from a book in my local library (I am just old enough to remember life before the mainstream internet!) — unfortunately I can't give any real clues to its identity. It was a paperback, A4-ish in size, glossy with perhaps 100 pages, monochrome photos throughout, and a grey/turquiose cover to match the Metrolink corporate identity of the time. Content covered construction, and the network's operation as it was initially. Publication can't have been later than 1996.
     
  7. Ken H

    Ken H Established Member

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    the old tram systems relied on a bloke standing in the street working points. and early traffic lights had a man pushing buttons on a cabinet to do the phases. before solid state electronics, automating logic relied on lots of relays.
     
  8. Deerfold

    Deerfold Established Member

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    Have TfL removed that since you posted the link?

    I used to work on the AVL system in London - we too used radio beacons around London - we had to tell the AVL system about the SVD beacons which worked in much the same way as ours except ours were battery powered and theirs were wired into the mains.
     
  9. Adlington

    Adlington Member

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    Something like this, from Flandres?
    Incorrect.
     
  10. Man of Kent

    Man of Kent Member

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    Possibly this book: https://www.abebooks.co.uk/9781872524368/Light-Rail-Systems-Manchester-Metrolink-1872524362/plp
     
  11. edwin_m

    edwin_m Veteran Member

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    Most junctions on most modern UK tramways have some form of tram priority. I was told that the only one that didn't in Nottingham was Parliament Street, but that was before the extensions so there may be others or there may even be priority there now.

    However priority is not absolute. In particular, if a tram passes in one direction there has to be a minimum green phase for conflicting road traffic, and if a tram arrives in the other direction during this time it will have to wait.

    The principles are in this publication, particularly Appendix B: https://webarchive.nationalarchives.../assets/pdf_file/0018/2637/rspg-2g-trmwys.pdf
    This document is contemporary with the original "modern" British tramways and more recent systems may use GPS instead of fixed detectors. I can't speak for bus priority, but I guess the GPS-based systems would work for that too.
     
    Last edited: 18 Mar 2019 at 20:40
  12. rebmcr

    rebmcr Established Member

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  13. glbotu

    glbotu Member

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    Despite the long paper about 'modern' priority techniques in Melbourne some of the tram routes still switch points with a stick. The driver gets out (with their stick) and switches the points. You can see this at the junction of Balaclava Road and Hawthorn Road.
     

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