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.