Loop services

Discussion in 'Allocations, Diagrams & Timetables' started by mervyn72, 17 Nov 2019.

  1. mervyn72

    mervyn72 Member

    Messages:
    166
    Joined:
    23 Jul 2015
    Thameslink's loop trains all terminate at Sutton and have a change of headcode, despite running to and from St Albans, so are technically two different services.

    Is there reasoning behind this when the Cannon Street and Waterloo loop trains do not?
     
  2. Registered users do not see these banners - join or log in today!

    Rail Forums

     
  3. Peter Mugridge

    Peter Mugridge Established Member

    Messages:
    10,587
    Joined:
    8 Apr 2010
    Location:
    Epsom
    I recall reading - probably on this forum - that it's something to do with preventing abuse of the direct trains rule for ticket validity.
     
  4. yorkie

    yorkie Forum Staff Staff Member Administrator

    Messages:
    45,799
    Joined:
    6 Jun 2005
    Location:
    Yorkshire
    The rumour I heard was that it was to thwart @RJ using the 'through trains' rule for ticket validity, though I don't know if that's actually the reason.

    To be fair it probably makes sense to advertise these trains to Sutton, rather than St Albans to St Albans via Sutton and the use of 'false destinations' en route.

    Some of the other loop services may be more problematical in this respect, in that there may not be an obvious place to change the service ID.

    As things stand, you can travel from Clapham Junction to Earlsfield via Kingston for the same price as a direct train. But SWR probably aren't bothered; a paper ticket for that journey is not cheap, and it's an irrelevance for PAYG.
     
  5. RJ

    RJ Established Member

    Messages:
    7,447
    Joined:
    25 Jun 2005
    Location:
    Rail replacement bus cab
    I would suggest there's no truth in such a rumour at all. I'm pretty sure this arrangement on Thameslink predates me and I've never been on their radar for ticketing matters. Furthermore, I've always openly discouraged abuse/misinterpretation of the through train rule when people try to advocate break of journey on otherwise illegitimate routes.

    They weren't always circular services anyway - for several years it was two interworked routes - Luton to Sutton and St Albans to Sutton.

    Some things I will claim but not this one.
     
    Last edited: 18 Nov 2019
  6. LA50041

    LA50041 Member

    Messages:
    741
    Joined:
    20 Feb 2017
    The Cannon st loop trains also change head code at either slade green or crayford
     
  7. stut

    stut Established Member

    Messages:
    1,861
    Joined:
    25 Jun 2008
    I think the Scottish loops have a similar split - the Cathcart Circle operates as a single headcode, but the Fife Circle seems to change over at Glenrothes with Thornton. Hamilton loop trains change over at Motherwell, but you can understand this, given the size of the loop relative to the rest of the line.

    Romsey loop changes over in, well, Romsey.
     
  8. swt_passenger

    swt_passenger Veteran Member

    Messages:
    21,710
    Joined:
    7 Apr 2010
    Not really a loop service is it, given the reversal?
    However the one train at start of service that actually does the full Salisbury to Salisbury clockwise via Eastleigh runs under one headcode:
    https://www.realtimetrains.co.uk/train/W37040/2019-11-18/detailed
     
  9. IrishDave

    IrishDave Member

    Messages:
    343
    Joined:
    30 Jun 2009
    Location:
    Brighton
    I wonder if it might have to do with odd/even numbering - all Thameslink trains northbound through Blackfriars end with an even number, and all southbound with an odd number. So somewhere it has to change from odd to even so as not to confuse the signallers by having an odd headcode going north (or an even one going south).

    In the London Bridge area for Southeastern, the split is odd numbers go to and from Cannon Street and even numbers go to and from Charing Cross, so keeping the same number all the way round the Cannon St-Cannon St loop is advantageous.

    Then again, Waterloo is generally odds departing and evens arriving, except for the loop trains which are all odd numbers...!
     
  10. 800002

    800002 Member

    Messages:
    556
    Joined:
    19 Jun 2019
    Is there also something to think about with ARS and Trust getting into a muddle with the same headcode effectively double backing on itself?
    I'm not sure of the 'loop duration' in the Waterloo /cannon st loops, ie the point it diverges and reconverges upon itself (thinking Lewisham in the case of the cannon St services) but could the Sutton loop be conciderably shorter this requiring a change in digits?
     
  11. Springs Branch

    Springs Branch Member

    Messages:
    639
    Joined:
    7 Nov 2013
    Location:
    Where my keyboard has no £ key
    Merseyrail operate a line (the Wirral) where almost every train goes around a compact loop and back along the same line to its origin. They manage this without any change of headcode en route. The third and fourth digits are a simple count up in increments of 1 from the first train of the day.

    The Wirral line is a self-contained, mostly isolated system, of course, unlike the Waterloo, Cathcart Circle etc examples mentioned.
     

Share This Page