Monday 13 January 2014

SkyCycle: Ticket To Ride or We Can Work It Out?

I have muttered a little bit about the concept and even suggested that we should stop giving oxygen to the idea, but I cannot contain myself any longer, I need to comment. I did surprise myself where my thoughts took me though.

The SkyCycle concept. Image from Foster + Partners.
I have been prompted to comment after reading a post by Stephen Fleming of Cycle Space. His post thinks beyond the criticisms of the scheme and offers plenty of positives, but you should also read Jim Davis' post on the scheme for another perspective. From my point of view, I want to concentrate on some of the physical aspects of the concept which has been developed by Space Syntax, Foster + Partners and Exterior Architecture.

For those living under a rock, the concept is essentially building a series of elevated cycle tracks above railway corridors in suburban London so that people can cycle in safety and comfort into the city or at least longer distances, which in itself is not a bad thing when compared to schemes such as the blue paint of the Superhighways.

The Shard. Something from Blade Runner or the 
personal hell of a window cleaner?
To me, architects have always been a slightly odd bunch. They are not always bound by the practicalities of building things and this is a good thing as they do challenge engineers and perhaps force them to up their game. I think The Shard is an amazing building, but my mind always wanders back to the poor sod who has to clean the windows!

Of course, most architects are like most engineers in that they get on with the day to day job of designing and building stuff which doesn't generate any headlines. I guess the difference is that there are a few famous architects out there whereas most people won't be able to name a living civil engineer.

Foster is a big international name and anyone with a passing interest in the built environment will have heard of him. He is no stranger to London of course. If I mention the London Millennium Bridge, you may not know what I mean. If I mention The Wobbly Bridge, you will know exactly what I mean. 

The London Millennium Bridge: with no wobble.
It is remembered as "wobbly" because of unforeseen problems with high numbers starting to walk "in step". Basically, vibrations start in the bridge because of people walking and the vibrations make the pedestrians walk in time which then amplifies into a very noticeable movement. 

As it happens, it was a cutting edge piece of bridge engineering (one of my favourites) and the problem was cured by the engineers using "dampers" (kind of like car suspension) to stop the movement. All is now well and it is a piece of London. But, Foster is remembered for it rather than the engineers who made the vision work.

SkyCycle does come from the high-profile, perhaps even "showman" kind of designers proposing a concept with very little information on how the whole thing is going to work, but it is enough to make the headlines (and possibly raise the profile of the smaller companies - they still need to eat after all). It has prompted a trial by Twitter and the Bloggers with complete dismissal by many.

Engineers are often accused of ignoring the concept and going straight for the problems (or it might just be me), but until there a list of the problems (or challenges if you prefer), we worry about how something will work. Look back at the concept drawing and you will see that the project is basically a continuous bridge deck supported by the gantries holding up the overhead power cables. This raises issues;
  • The gantries are designed to hold up the cables (under tension with weights every so often) and not a structure above. The gantries would need replacing with something up to the job, or independent support is required.
  • How will the underside of the bridge deck be inspected with power cables between the ground and the cables as these things need to be checked from time to time.
  • Of course, many rail lines are not powered overhead, they are powered by a third rail and so these routes would need stand alone bridge deck support.
  • How will any inspections take place as the line would need to be closed to do so. OK, Network Rail inspects its kit and this would just be another thing on the list, but extra work.

A particularly hideous footbridge over the High Speed 1 railway.
High parapets with a roof cage - is this what SkyCycle will really

look like?
More generally, there are other issues;
  • The Railways don't like stuff chucked over the sides of bridges onto the track and so where bridges (especially footbridges) cross tracks, they tend to have high parapets (footbridges often have cages on top!). The concept suggests transparent parapets which would be madly expensive. Of course, without a clear view, then concept fails as a nice place to be!
  • Many railways are in cutting and the SkyCycle bridge deck will nicely end up at a level overlooking houses and gardens. Where railways are on embankment, the view will be even better.
  • What will happen at locations where the railways go under roads, as in most cases, there is only limited clearance. In some locations, there is no clearance as the cables attached to the over bridges. Will SkyCycle sail up over the road bridge and back down the other side? Roads need just over 5 metres clearance for vehicles and so we could end up with some huge approach ramps and SkyCycle way up in the air! Many bridges are "humps" over the railway anyway. (Although I guess SkyCycle could be accommodated with Toucan crossings at the roads!)
The SkyCycle over Barking Station.
Image adapted from Google Streetview.
  • Many stations on suburban railways are above the level of the railway and often within a parade of shops. Will SkyCycle sail over the top of the buildings?
  • Access ramps to SkyCycle will need to be very long to be useful and so land take to the street network away from the railway will be problematic.
  • We also have the inevitable questions of build and maintenance costs (who will pay) and if users will be charged. Plus (quite rightly) campaigners are worried that it could suck money it at the expense of other much needed local infrastructure.

There will be lots of other things that I haven't thought about, but it doesn't appear the designers have either. Had we seen press releases with a little more detail, then people may not have been so scathing or dismissive as there is some merit in the concept (gasp!).

Using a rail corridor for something else in London. Ridiculous.
Oh. Wait. Hungerford Bridge.
Image from Google Streetview.
If you look around London, there are many railways which cross over or are crossed over by the road network. South London has its low railway bridges over roads, East London has its hump-backed bridges over railways. 

Highway space often narrows right down at bridges and so if we are looking at access for people on bikes, they are squeezed in with road traffic and pedestrians often have narrow footways. We also have the Thames which cuts London in two and so the idea of using railway corridors might actually help create links between areas which are horrible to get between now.

The concept of building of permanent ways above streets and railways is also nothing new, just look at some of the urban viaducts of the M11/ A406 junctions or the Docklands Light Railway. Providing elevated space for cycling (and walking) might actually create direct, convenient links.

So, while I remain hugely sceptical about the scheme as a whole, there are some problems that short sections of SkyCycle can solve when railway land is thought of as space available to facilitate cycling bridges or viaducts. Perhaps we are just too quick to judge things these days, but equally, people with ideas need to give some detail or they will be dismissed. 

I do worry, though, that the show-boating we get from some professionals does rather take attention away from a lot of the basic day to day things we should be doing now. These interventions are never celebrated, but nor do their designers seek celebrity. Most of us do this kind of work as our day job and that is why you haven't heard of us!


  1. Foster is a twat...when the Millennium Bridge got its wobble he famously walkjed away and dismissed it as "an engineering problem", ta for that!

    As for the Sky Cycle, can you tell an engineer from the provinces where these money trees are that London seems to grow in abundance, and is it possible to get cuttings? The lucky 'Cycle Cities' received central government funding of less than £20m each and are supposed to be grateful for it and somehow create fantastic cycle infrastructure with it. Meanwhile London idly discusses pissing away £100s of millions on a 'grand projet' without a thought.


    1. A bit of twattery is probably a good thing :)

      The money trees never seem to sprout in my corner of London judging by my budgets!

  2. "To me, architects have always been a slightly odd bunch. They are not always bound by the practicalities of building things...I think The Shard is an amazing building, but my mind always wanders back to the poor sod who has to clean the windows!"
    I always say the difference between an architect and an engineer is typified by the glass roof of the Great Court at the British Museum (coincidentally also designed by Foster). Over 3,300 panes of glass - each one a unique shape. If that were designed by engineers there would be one standard shape, it would achieve the same effect and cost half as much. ;-)


  3. Great post! Can we start brainstorming solutions? A few of these problems would be solved if the routes were enclosed, which also open the spectre of back-drafting. Where roads cross train lines, we would be looking at on-grade crossings—where possible, anyway. I take the point about inspection of wires. Does that mean those trains don't run in tunnels?

    1. The overhead cables do go through tunnels and bridges, often attached to the crown/ soffit. In these places, that's where the SkyCycle would have to rise up and over as it would fit under the bridges or through the tunnels.

      There is a Greenway which runs from Beckton to Stratford which sits on top of a huge embankment within which there are sewer pipes. This has at-grade crossings where roads cross and gives permeability.

    2. sorry, we've spoken at crossed purposes (slightly). I was wondering if running a platform over electric wires would be such a big problem for maintenance and inspection, given wires are just as hard to get to in tunnels. (Thanks for clarifying that wires do run in tunnels—I wasn't sure).

  4. By way of a warm-up, the problems of the "wibbly-wobbly bridge" were entirely predictable and should have been foreseen by Foster & Partners in their design. Why? Just look a little further upstream, at the Albert Bridge, which has had this message attached at the ends since Victorian times - "All troops must break step when marching over this bridge"

    Similarly, we have recently seen an excellent short film much linked on Twitter, about the elevated walkways conceived by the City of London, but now substantially abandoned, either never built or closed off, apart from around the barbican. Mercifully, such hellish Corbusian visions are largely confined to the Brazilian Amazon jungle or to Ceausescu’s Bucharest. Anyway, it tells us something about the prospects for elevated cycle ways.

    I haven’t sat down and thought of all the practical issues you have identified here, but none of them surprise me, and perhaps they explain the anomaly in the projected costings – I had assumed that the £220m quoted was for the entire network but others have read the publicity to say that this refers only to the first 6km pilot project – that is pretty much the cost of non-urban motorway.

    But I will admit that perhaps the wilder shores of architecture could throw up some interesting ideas at a more practical level – just like Paris fashion week displays unwearable clothes which nevertheless set the style of the next season’s wearable ones. An obvious place to start has to be bridges. These are by and large very unpleasant and often dangerous places for cyclists – somehow they all seem to have a free stretch between two bottlenecks which leads to speeding and reckless driving over the bridge itself. Why not hang cantilevered pedestrian/cyclist decks off the side of most road bridges eg London Bridge, Waterloo, Blackfriars, after all it is not as if it would harm their appearance much? Or build a cycle bridge using the redundant pylons of the old railway bridge between Blackfriars road and rail bridges?

    I have also always thought that there should be potential for creating cycle tracks alongside railway lines, not just in London but anywhere. Railway track tends to have only modest gradients and wide curves, so if some space could be freed up alongside and adequately fenced to prevent the inevitable dickheads trespassing on the line, hey presto you have a new traffic-free path! Actually, out in the country, there are plenty of places where pedestrians can already access the track where public footpaths cross on uncontrolled level crossings, so what’s the problem? Also, Network Rail usually owns a reasonably broad strip of land either side of the track edges anyway.

    1. Good comments. For me, the positive to come out of the show boating is getting my brain thinking and that is a good thing.

    2. I haven't been to Minneapolis but understand they have extensive bike infrastructure beside (not above) working train lines.
      And I agree: hang bike routes beside road bridges. You can turn the carriageways themselves into non-vehicular routes once you have outnumbered the car driving voters with cyclists.

  5. A very good article and, may I say, one of your better titles :o)

    It was really interesting to consider this proposal from a practical point of view. You make some very valid criticisms—pretty much all of which I hadn't really given any thought to, and all of which would need to be dealt with properly if this proposal was to be taken forward.

    I had looked at this from the perspective of how this scheme would fit in with everything else, and I hope you don't mind if I share my thoughts with you here.

    Regarding the proposal of a route from Stratford to Liverpool Street, I think if I was travelling some distance, then this route may be of use to me. But say I lived about halfway between the start and end points, what then?

    Actually the halfway point is Mile End Park, roughly, and obviously there would be space here for a ramp up to the skyway. Would I use the skyway, however, particularly if I had to pay to use it? What if there was an alternative route available as well?

    There is. (

    Generously, I have started and ended my hypothetical journey in places that confer a natural advantage to the skyway route. Even so, the journey distance is only a third of a mile further.

    All things considered, I suppose the skyway route would save me about five minutes, and there may be times when those five minutes would matter. But if I was just wanted to pootle along, and stop off at the bakers on the way, I'd probably give the skyway route a miss.

    Finally, this comment of yours made me smile: "people with ideas need to give some detail or they will be dismissed."

    1. Of course, on a nice summer's day, 5 minutes extra on a proper cycling expressway (to coin a term) would be an awful lot nicer than being wedged under an armpit on the train!

  6. If this were a serious goer then you could always borrow an idea from, where else, the Netherlands, and use escalators rather than massive ramps.

    Of course that being a Dutch invention it can immediately be dismissed...they know nothing about cycling in a really big city...London is unique and must have a unique solution. I suggest a needlessly complicated catapult and parachute arrangement.


    1. Nice! Now that would have been more use than the Dangleway!

    2. I've used the maastunnel escalator quite a few times. Everyone living there knows to turn their front wheel through 90 degrees. Failing to do so, could cause quite a tumble. I would be interested to know if the liability for an accident would rest with the user or designer if this system were used outside the Netherlands.

  7. I agree that bike routes next to railways would be something work looking at, but obviously depends on location. From London's point of view, many railways are built right up to and so it would be harder.

    For the whole platforms about overhead lines issues, I am sure it is technically feasible, it is just that for inspections, it would need to take place when the power is off and the line closed which is tricky where operating hours are long!