AVRT- an idiotic proposal for Cambridge

Discussion in 'Other Public Transport' started by jopsuk, 31 Aug 2017.

  1. jopsuk

    jopsuk Veteran Member

    Messages:
    11,848
    Joined:
    13 May 2008
    "Affordable Very Light Rapid Transit" is a proposal that's been funded by the City Deal (now Greater Cambridge Partnership) as a concept for public transport in and around Cambridge
    details are here
    Part 1
    Part 2

    Roughly speaking, it consists of 40-seater self steering 8 wheel electric buses running shuttles along tunnels. If (for example) you come in to the city from the south and want to get to the north, then you'd have to change.

    Twice

    Look at pages 12-13 in part 1 for the best laughs.

     
    Last edited by a moderator: 2 Sep 2017
  2. Registered users do not see these banners - join or log in today!

    Rail Forums

     
  3. pdeaves

    pdeaves Established Member

    Messages:
    1,816
    Joined:
    14 Sep 2014
    Location:
    Gateway to the South West
    I for one remain to be convinced that anything tunnelled would be 'affordable'!
     
  4. Bald Rick

    Bald Rick Established Member

    Messages:
    8,074
    Joined:
    28 Sep 2010
    Especially in Cambridge, famed for being built on good ground for tunnelling.
     
  5. Shaw S Hunter

    Shaw S Hunter Established Member

    Messages:
    1,964
    Joined:
    21 Apr 2016
    Location:
    Sunny South Lancs
    Laughs? Actually that's a very logical set of statements and with the developments currently happening with both battery power and autonomous vehicles such a system could very well be built somewhere in the not too distant future. I for one will not be mocking the concept as a whole.

    The real question is whether the reduction in costs that appear to be possible will go far enough to make it affordable in a given situation. Cambridge is something of a scientific hub these days so it is no surprise that such an idea has surfaced there. My own suspicion is that Cambridge is too small to make the numbers work. A better location would be somewhere a little bigger that is also blessed with fairly easy topography for underground construction, ie flattish and without a significant waterway to worry about. The problem is that large towns/small cities tend to grow around rivers, often in a tightish valley, so it's difficult to come up with such a potential test location. Perhaps Swindon: nearly twice the population (apparently) of Cambridge or even Milton Keynes (even bigger and still growing).
     
  6. jopsuk

    jopsuk Veteran Member

    Messages:
    11,848
    Joined:
    13 May 2008
    Part of the problem with the diagrams on page 11/12 is that they seem to have wilfully ignored tube trains.
     
  7. whittlesfordok

    whittlesfordok Member

    Messages:
    44
    Joined:
    20 Jan 2014
    As usual they seem to miss that the east west line is coming. Also the present line to Ipswich is missing. Knowing how Cambridge floods it will cost a lot more than their budget.
     
  8. daikilo

    daikilo Established Member

    Messages:
    1,523
    Joined:
    2 Feb 2010
    For reference, the deep level London underground runs in tunnels of approximately 3.6m diameter and the Glasgow subway 3.35m, so 3.7m is potentially quite generous, until you start packing in the rolling and guidance mechanics, batteries and aircon in a single vehichle.

    Also, from a building cost viewpoint, having 4 central terminuses is not as efficient as say 2 cross-centre lines (could each be and L to avoid the need for one to cross beneath the other).

    Personnally, I see it as a generic university modelling project, at this stage, rather than one which fully addresses how to actually achieve it in a specific environment. As such, and given the details provided, I cannot agree with the thread title, it cannot be idiotic, maybe a bit short on certain answers, and somewhat optimistic.
     
    Last edited: 2 Sep 2017
  9. gordonthemoron

    gordonthemoron Established Member

    Messages:
    5,836
    Joined:
    4 Sep 2006
    Location:
    Milton Keynes
    The interchange on page 22 of section 1 looks suspiciously like a swastika
     
  10. TheDavibob

    TheDavibob Member

    Messages:
    318
    Joined:
    10 Oct 2016
    This idea did slightly confuse me, yes. The most important alignment as things stand is West-South, with North-East a project that can be added later. Thus, no reason for a central terminus. My biggest gripe with this project is the determination to avoid intermediate stations which, while operationally maybe quite nice, makes it a system that solely caters for out of town commuters and is broadly useless at all other times.

    A simple West - centre - station tunnel (with maybe three intermediate stops) would easily be able to hit an average speed of 20+mph, which frankly is all that's needed, and caters to commuters (with a suitable western P&R, or connecting to a busway-style thing, or a continuation of a busway style thing), tourists (the station-centre connection would be dealing with several thousand people per hour) and locals (to the station, and later to Addenbrookes).

    Further, there would be exceptional pressures on a single central terminusy thing to distribute passengers, especially due to the range of destinations of commuters.
     
  11. MarkyT

    MarkyT Established Member

    Messages:
    3,190
    Joined:
    20 May 2012
    Location:
    Torbay
    For their control concept they seem to have reinvented the concept of absolute or token block with only one vehicle moving on each link at a time. Glad to see Cambridge, the city of learning and high tech research (and incidentally of my birth), is keeping up with the times! They will still need a high integrity processing and communications system to issue their movement authorities however and confirm that one vehicle is clear of the section before authorising the next. That's more complexity than many traditional trams, yet they're claiming 'no signalling'. I don't really understand. Perhaps they're under the impression that no traditional signals means no signalling, whereas in fact most costs in control systems arise from the less obvious bits you can't see, the safety critical sensors, cables, interlockings, radio systems etc (and their expensive bespoke configuration). I can't see how they're avoiding these even if they aren't proposing lights on sticks, or needing junction point machines.
     
  12. Shaw S Hunter

    Shaw S Hunter Established Member

    Messages:
    1,964
    Joined:
    21 Apr 2016
    Location:
    Sunny South Lancs
    Given the proposal is for rubber-tyred vehicles stopping distances will be much shorter than steel-wheels-on-steel-rails so the issue of maintaining separation is somewhat less critical. There could be the possibility of autonomous line-of-sight driving using radar over much of the network. An overall system of control is certainly needed to maintain the timetable but it doesn't have to resemble a current metro in too many details.
     
  13. MarkyT

    MarkyT Established Member

    Messages:
    3,190
    Joined:
    20 May 2012
    Location:
    Torbay
    Agreed, I was thinking about what they describe regarding "shuttling" operations in Appendix 1 of the 1st part. For single track tunnel operations they will need some form of more sophisticated coordination for 'token' issue and collection to prevent deadlocks. Even if theoretically two cars heading towards each other at full speed were able to detect each other in time and both brake to a stand clear of each other safely every time, in a narrow tunnel environment they wouldn't then be able to pass without one backing up all the way to it's original departure point, so it would be a big performance problem to admit two such conflicting movements at the same time, even if the 'SIL4' collision prevention layer was entirely managed autonomously by the vehicle itself. It might be that such a 'token issuing' side of control need not be such a high integrity system as it would have to be in a railway environment, so possibly cheaper and able to be built from more general purpose equipment.
     
  14. eastdyke

    eastdyke Established Member

    Messages:
    1,322
    Joined:
    25 Jan 2010
    Location:
    East Midlands
    The 'Cambridge Metro' appears to have taken a small step forward:
    http://www.bbc.co.uk/news/uk-england-cambridgeshire-42890761

    There is some discussion up-thread about suitability of ground conditions for tunnelling under Cambridge. I note that the original 'Report 1' referenced in the OP asserts the opposite at page 20:
    Quite apart from the radical concept, there seems to be absolutely no consideration of how passengers would be evacuated in the event of a break down, or heaven forbid a fire, affecting any 'unit'.
     
  15. Adlington

    Adlington Member

    Messages:
    678
    Joined:
    3 Oct 2016
    Why this should be different from evacuation from any metro tunnel?
     
  16. MarkyT

    MarkyT Established Member

    Messages:
    3,190
    Joined:
    20 May 2012
    Location:
    Torbay
    I think Cambridge should look at the Warwick Uni work on autonomous very light rail.
    https://warwick.ac.uk/newsandevents/pressreleases/very_light_rail/

     
    Last edited by a moderator: 13 Feb 2018
  17. Bletchleyite

    Bletchleyite Veteran Member

    Messages:
    34,817
    Joined:
    20 Oct 2014
    Location:
    Up and down the south WCML (mostly)
    I think Cambridge probably justifies a street running tram network, myself. The Busway could be converted as Edinburgh’s was.
     
  18. Adlington

    Adlington Member

    Messages:
    678
    Joined:
    3 Oct 2016
    Interesting snippet from Part 2 (see 1st post), page 2:
    (my emphasis)
     
  19. eastdyke

    eastdyke Established Member

    Messages:
    1,322
    Joined:
    25 Jan 2010
    Location:
    East Midlands
    Which requires what?
    Is it a road tunnel, a rail tunnel or something else?
    I suggest that building a single bore (as some of the options and cost might dictate) would not permit cross bore connections for access and evacuation. If it is either road or rail then they would almost certainly be mandated over such long bores (circa 4km +).
    If 'road' they would be the longest road under-land in the UK by quite some way, so we may have
    UK experience of tunnelling but not of designing and building anything quite like this.
    If 'rail', then taking Crossrail as a reference, this has both full length walkways and cross bore connections.
    Longitudinal forced ventilation systems would also be needed in all cases.
    Further, autonomous vehicles would mean that information to passengers in the event of an incident might be more difficult. It is important that passengers be told what to do, including to leave a unit in the first place and to 'walk the right way' towards safety.
    I think that the concept of 'Cambridge Underground' is fine on paper and in talk but is of insufficient scale to justify its construction. Safety design is never that cheap.
     
  20. Ianno87

    Ianno87 Established Member

    Messages:
    3,829
    Joined:
    3 May 2015
    The full report of all the options (daft* and non-daft) is well worth a read:

    http://www.cambridgeshirepeterborou...it-options-assessment-report-January-2018.pdf

    Basically argues that an Autonomous Metro (I.e. Guided tram without rails) is better value for money. The population density of the area served (Cambridge is relatively small, then the surrounding area is pretty scattered) doesn't justify the number of stops on a conventional tram and thus neither the extra infrastructure cost of rails and what have you.

    Personally, I'm a little sceptical about such faith in fairly unproven technology, and I think there's scope to do more work to refine the tram into a more realistic and value for money proposition by reviewing where it serves - the report just tests the fairly extensive Cambridge Connect proposal as a given (rather than if something a bit less ambitious would be better value), rather than a single 'Line One' type scheme.


    *Cable cars and monorails soaring above Kings College chapel, and 120mph 18 seater tunnelled buses.
     
  21. TheDavibob

    TheDavibob Member

    Messages:
    318
    Joined:
    10 Oct 2016
    I saw a discussion with the consultants a few months back, and they suggested the DfT is very actively against new street-running tram networks. Can't remember the specifics, but I'll see if I can dig up a link.

    Also, a problem with the metro actually being buses is that it raises the question of the appropriate sub-forum...
     
  22. Bletchleyite

    Bletchleyite Veteran Member

    Messages:
    34,817
    Joined:
    20 Oct 2014
    Location:
    Up and down the south WCML (mostly)
    Is that because of the embarrassment that was Edinburgh? Though that was a mismanagement problem, not a tram problem. None of the other networks have suffered from it.
     
  23. TheDavibob

    TheDavibob Member

    Messages:
    318
    Joined:
    10 Oct 2016
    Yeah, it surprised me too. They've mostly been successful, and where they haven't (Brum most obviously) it's because they aren't quite going to the right place/enough of a network.
     
  24. Bletchleyite

    Bletchleyite Veteran Member

    Messages:
    34,817
    Joined:
    20 Oct 2014
    Location:
    Up and down the south WCML (mostly)
    FWIW I've had a quick read through the document, and I'm surprised an allegedly professional consultancy has produced such an utter load of garbage.

    1. How on earth do they think those low costs can be achieved using a system involving tunnelling, which is hugely expensive compared with street running trams?

    2. There is no consideration given to long-term costs. Street-running trams are a mature technology used worldwide, and the market for the technologies used in them is also mature with significant competition. Therefore, when it comes to replacing vehicles they are affordable and available and will continue to be so, and new technologies will be added to them on an evolutionary basis, be that things like off-wire battery operation (to be deployed in Birmingham) or ATO of some kind. (Automatic operation of a tram is a much easier technical problem than automatic operation of a steered road vehicle - all it has to do is see if its path is clear and if not stop).

    3. 120mph on non-physically-guided rubber tyres? Other than BMWs on the Autobahnen, that has not been delivered anywhere else in the world. It is likely to have serious safety concerns as well as be incredibly inefficient compared with steel on steel due to high levels of friction.

    This all rather smacks of the Simpsons "Monorail" episode. The sensible thing to do in my book is a street running tram with some segregation as achievable. Part of that would be P&R provision, and as with the guided busway that would significantly reduce traffic - people as a whole like trams and will flock to them provided they are built in the right place.
     
  25. Bletchleyite

    Bletchleyite Veteran Member

    Messages:
    34,817
    Joined:
    20 Oct 2014
    Location:
    Up and down the south WCML (mostly)
    You mean, I guess, one of those "bendy bus that looks like a tram and follows dotted lines on the road or a buried transmitter cable" things?

    Might be slightly cheaper short-term, but you're tied into one patented technology and the vehicles won't last as long, so while it might be cheaper to start with it's a false economy long-term in my view. If you build a standard two-horses'-backsides tramway with 750VDC overhead and low-floor vehicles, you've got any one of about 5-6 manufacturers worldwide (possibly more) competing for your business when you need vehicles for it. And while the rails are a bit expensive to lay, they will last well, you won't have to resurface the road to remove the dips that will develop as a result of very precise tracking of rubber tyred vehicles etc.

    And regarding ATO there is almost no difference between the two in terms of its design and application, if it is decided to go that way.
     
  26. Ianno87

    Ianno87 Established Member

    Messages:
    3,829
    Joined:
    3 May 2015
    Worth noting that the consultancy are not the people that came up with these ideas; it's just comparatively assessing their feasibility of a variety of stuff that had been proposed. The ideas themselves come from a wide range of promoters/peddlers, and some from non-transport professionals (the pretty good Cambridge Connect tram proposal is not from a transport-y person, for example). Unfortunately, a few smack of the "look at my clever theoretical academic solution. Now where's a problem for it to solve?" variety (it is Cambridge, after all) without any consideration of practical real world application. The report does do a good job of ruling some dafter ideas out once and for all.

    The report does (in the interests of time presumably) take each scheme "as proposed" to compare, rather than trying to perfect each idea before comparison. Admittedly, this may lead to a slightly skewed conclusions (better optimised scheme A is better than not quite so optimised scheme B).
     
  27. AM9

    AM9 Established Member

    Messages:
    6,160
    Joined:
    13 May 2014
    Location:
    St Albans
    The first impression that I have of the report is that only an 'all-carrot' solution need be considered. So they think that comparatively large volumes of private vehicles clogging a street plan of typical Anglo-Saxon market towns can be reduced just by offering easy public transport without any penalty for continuing private vehicle use. Despite a few streets being restricted for cars, most of the delays suffered by buses are down to the sheer volume of cars, and a range of measures are available that could make a significant difference without spending 10 figure sums. That could be implemented before the welter of electric and autonomous vehicles arrives, of which I would expect Cambridge to have many early adopters.
     
  28. eastdyke

    eastdyke Established Member

    Messages:
    1,322
    Joined:
    25 Jan 2010
    Location:
    East Midlands
    I am sure that the stick will follow in the form of a congestion charge.

    Before that happens there is a need to provide more P&R capacity (because that is what the 'recommended scheme' is) as the current 5000 odd spaces spread over the 5 existing sites simply isn't enough. OK plus a few more 'bus' services into the city from further out as well.

    I used to visit the City on a regular basis around 20 years ago and had to park in the central area. At that time I remember all day parking in Lion Yard was £13. I was surprised that it has gone up to 'only' £25 today.
     
  29. edwin_m

    edwin_m Veteran Member

    Messages:
    14,103
    Joined:
    21 Apr 2013
    Location:
    Nottingham
    The West Midlands is actively pushing ahead with extensions under a City Deal, and DfT could probably have stopped this if they had wanted to. I don't really see the distinction - if they are in favour of extensions why would they not be in favour of new networks.

    Also snow and ice isn't unknown in Cambridge, and could interfere with either the navigation or the physical steering of a vehicle that doesn't have a "hard" guidance system.

    Interestingly the German and Swiss approach to urban transport, much hailed on this forum including by me, is mostly carrot-based. But it would probably need a much wider-area approach to make it successful in Cambridge without significant amounts of "stick", since I imagine many of the cars come in from places some distance out where the public transport is probably pretty atrocious.

    Despite some of the above, I remain highly skeptical of any proposal for a tram in Cambridge (they come up every few years). To access the centre they really need to traverse the extremely narrow streets between the Market Place and the bottom of Castle Street. The other problem is hordes of cyclists, who basically take over the entire road at certain times so would delay the trams as well as being at risk from the rail grooves. I haven't had a chance to look at this report as yet and I may comment further when I do.
     
  30. TheDavibob

    TheDavibob Member

    Messages:
    318
    Joined:
    10 Oct 2016
    The Greater Cambridge Parternship (née the City Deal) is determinedly forging ahead with plans for "busways" (unclear about their guided nature) towards Haverhill in the south-east (via the old railway alignment) and towards Cambourne in the west, with some less developed proposals towards Waterbeach in the north. They wish now to link these into the CAM system discussed here, which actually provides a reasonable argument for no tracks (especially as it would allow buses to stay at street level if appropriate, yet still use the new infrastructure). I'm not sure there's much justification for such a long-range light rail network, however making buses "better" might have more legs.

    Yeah, cyclists are my primary quibble with street-running trams in Cambridge. There is no way (to my mind) a tram could cross the historic centre itself, and even shirking it (as buses do now) the increase in danger at the foot of Castle Hill and along Bridge Street (where it would have to be single-track) would be unpalatable. A tram route would (to my mind) have no choice but to cross the river quite some way East, which would reduce city-centre penetration (not that anybody works there anyway, so it wouldn't entirely be the end of the world).
     
  31. Bletchleyite

    Bletchleyite Veteran Member

    Messages:
    34,817
    Joined:
    20 Oct 2014
    Location:
    Up and down the south WCML (mostly)
    I can't see any reason why not, particularly if batteries could avoid the need for OHLE.

    I don't agree. Trams, unlike huge volumes of cars, or large buses, are really good for going through tight city centres. Once you've worked out the swept path they are never going to do anything other than follow it precisely.

    Furthermore, most designs can be built to varying widths due to what is already there around the world (the UK ones are typically quite wide, but that's just because that was what was appropriate where they were built). A narrow design with 2+1 seating may well suit Cambridge to get through narrow streets.

    Cyclists will cope, they do elsewhere.
     

Share This Page