STP (short term plan) vs VAR (variation)

Discussion in 'Allocations, Diagrams & Timetables' started by CheapAndNerdy, 25 May 2015.

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  1. CheapAndNerdy

    CheapAndNerdy Member

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    Looking at Realtime trains at Clapham Junction I notice a sea of STPs and virtual no VARs. I always thought that STP, as the name suggests, was used for services that were added to the system at short notice due to an unexpected incident, while VAR was used for tweaks to an existing service.

    In the above example, most (all?) of these STPs have associated CANs. While it may not make much difference overall I wonder why it has been done like this. By contrast, services through Reading are making far more use of VARs.

    Just curious.
     
  2. heart-of-wessex

    heart-of-wessex Established Member

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    Would that not be VSTP for unexpected incidents? I suppose it depends how long it is before very short term planning is needed. I thought STP would be for one-off's and irregular movements, I may be wrong as I'm not a planner, just judging be what I've seen in the past
     
  3. Poggs

    Poggs Member

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    VSTP is another mechanism for pushing through a schedule - which can be either a VAR, an STP, or a cancellation.

    Schedules that come through the normal timetabling process, including the STP process, are validated by ITPS. Those that come through via VSTP aren't.
     
  4. 306024

    306024 Established Member

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    VAR would be a schedule that is a variation of the base permanent LTP (long term plan) schedule. It can be something as simple as a planned platform alteration, or maybe a booked train terminating short of its destination, or starting forward of its normal origin.

    STP would be a schedule that is so significantly different to an LTP schedule that a variation is not appropriate. Today being a Bank Holiday Monday, many South East TOCs such as SWT simply cancel off the planned Monday service and replace it with a service based on a Saturday or Sunday. STP schedules can be published up to 12 weeks ahead, hence the sea of STPs.

    Elsewhere such as Cross Country for example, a variation to the normal Monday schedule may be more appropriate. Basically whatever method causes the planners least replanning is used.
     
    Last edited: 25 May 2015
  5. CheapAndNerdy

    CheapAndNerdy Member

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    Now I understand. Today's timetable is not simply an adjusted weekday one, but is (in Southern land) based on Saturday's, even if they might be broadly similar in frequency and timing. That explains it. Thanks.
     
  6. 306024

    306024 Established Member

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    You're welcome, happy to explain. There are those that say planning is a dark art, but it is all quite logical really once you understand what's involved.
     
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