London's Tube has been running so long it's literally raising the temperature of the earth around it

Londoners swelter on the Central line during the heat wave of 2003. Image: Getty.

“Why is the tube so hot?” is one of those questions Londoners find themselves asking a lot during the three or four days a year when the city’s weather isn’t completely bloody miserable. But it’s not something to which I’ve ever given much thought. Lot of people, enclosed space – the reasons are obvious, surely?

Except, not every underground railway in the world has this problem. And once upon a time, London didn’t either: when the Bakerloo line first opened, posters suggested it was a good place to keep cool on a hot day, an idea that’s clearly nonsensical in 2017.

And then, from the Twitter feed of occasional CityMetric contributor @LeftOutside earlier*, I learned something genuinely amazing:

My mind, as the kids say, is blown.

And it’s true. In 1900, according to this fascinating article in Rail magazine, the ambient heat of the earth surrounding the tunnels – clay, mostly – was around 14°C. In the height of summer, the tunnels were indeed colder than the air above, so it made sense to travel by tube to cool down.

The problem is – trains full of people tend to give off heat. According to this article from a 2007 edition of Plant Engineering magazine, the vast majority (89 per cent) of that heat comes from the train itself (the friction during braking is the big one), 7 per cent from passengers and 4 per cent from “Tunnel support systems”.

What happens to this heat? On the sub-surface lines – basically, those which share tracks with the Circle – it’s not too big a problem. The tunnels are close to the surface, so often emerge into the light for brief periods (Barbican, South Kensington and Edgware Road are all above ground). They also have plenty of ventilation shafts. The heat has somewhere to go.

The deep tubes, though – the ones which are literally tunnels bored through the ground – are more problematic. Most of them are old, so were built before anyone realised heat would be a problem, and don’t come with enough ventilation shafts to solve it. The air is trapped. And so, the heat is absorbed by the walls, and the earth behind them.

In 1900, as noted above, the average ambient temperature was 14°C. Some 117 years and millions of trains later, it can be anywhere between 20°C and 25°C.


 Let’s just say that again: London has been running tube trains so long that the ground beneath parts of the city is now as much as 10°C hotter than it was in 1900.

One result of this is that the earth has become much less effective at absorbing the excess heat. That means the tunnels themselves have heated up, too. A lot: air inside them can often reach as high as 30°C. You’ve probably noticed this is you’ve been on the tube recently.

For the last decade or so, Transport for London has been looking for solutions to this. Some of them involve increasing the capacity of existing ventilation systems (lack of space above ground means it’s extremely difficult to build new ones). Others involve adding systems which circulate water to cool the air. Yet other options involve things like more efficient braking systems, on the grounds that if you put less heat in, you have less to take out.

Experimental air coolers on the Victoria line. Image: Oxyman/Wikipedia Commons.

It’s clear that there’s no easy solution, however: in 2003, then London mayor Ken Livingstone offered a prize of £100,000 to anyone who could come up with fresh ideas. Nobody could think of anything TfL wasn’t already trying, and the prize went unclaimed.

The upside to this story is that other cities have learned from London’s mistakes, and ensured that ventilation systems are an integral part of new metro systems.

The downside is you’re likely to boil every time you get the Central line in summer for the foreseeable future.

*LeftOutside has since been in touch to tell me he was summarising another article, from the Ian Visits blog. I haven’t read that one – the above article is drawn from the two articles I reference, plus some bits from TfL. But in the name of politeness and an easy life I'm acknowledging its existence and adding a link. Read that too, if you like. 

Jonn Elledge is the editor of CityMetric. He is on Twitter as @jonnelledge and also has a Facebook page now for some reason. 

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Owning public space is expensive. So why do developers want to do it?

Granary Yard, London. Image: Getty.

A great deal has been written about privately owned public space, or POPS. A Guardian investigation earlier this year revealed the proliferation of “pseudo-public spaces”. Tales of people being watched, removed from or told off in POPS have spread online. Activists have taken to monitoring POPS, and politicians on both sides of the pond are calling for reforms in how they are run.

Local authorities’ motives for selling off public spaces are normally simple: getting companies to buy and maintain public space saves precious public pounds. Less straightforward and often overlooked in this debate is why – given the maintenance costs, public safety concerns and increasingly unflattering media attention – developers would actually want to own public space in the first place.

To answer that question it’s important to note that POPS can’t be viewed as isolated places, like parks or other public spaces might be. For the companies that own them, public spaces are bound up in the business that takes place inside their private buildings; POPS are tools that allow them, in one way or another, to boost profits.

Trade-offs

In some cities, such as Hong Kong and New York, ownership of public space is a trade-off for the right to bend the rules in planning and zoning. In 1961 New York introduced a policy that came to be known as ‘incentive zoning’. Developers who took on the provision of some public space could build wider, taller buildings, ignoring restrictions that had previously required staggered vertical growth to let sunlight and air into streets.

Since then, the city has allowed developers to build 20m square feet of private space in exchange for 80 acres of POPS, or 525 individual spaces, according to watchdog Advocates for Privately Owned Public Space (APOPS).

Several of those spaces lie in Trump Tower. Before the King of the Deal began construction on his new headquarters in 1979, he secured a pretty good deal with the city: Trump Tower would provide two atriums, two gardens, some restrooms and some benches for public use; in exchange 20 floors could be added to the top of the skyscraper. That’s quite a lot of condos.

Shockingly, the current president has not always kept up his end of the bargain and has been fined multiple times for dissuading members of the public from using POPS by doing things like placing flower pots on top of benches – violating a 1975 rule which said that companies had to provide amenities that actually make public spaces useable. The incident might suggest the failure of the ‘honour system’ under which POPS operate day-to-day. Once developers have secured their extra square footage, they might be tempted to undermine, subtly, the ‘public’ nature of their public spaces.

But what about where there aren’t necessarily planning benefits to providing public space? Why would companies go to the trouble of managing spaces that the council would otherwise take care of?


Attracting the ‘right sort’

Granary Square, part of the £5bn redevelopment of London’s Kings Cross, has been open since 2012. It is one of Europe’s largest privately-owned public spaces and has become a focal point for concerns over corporate control of public space. Yet developers of the neighbouring Coal Drop Yards site, due to open in October 2018, are also making their “dynamic new public space” a key point in marketing.

Cushman Wakefield, the real estate company in charge of Coal Drops Yard, says that the vision of the developers, Argent, has been to “retain the historical architecture to create a dramatic environment that will attract visitors to the 100,000 square feet of boutiques”. The key word here is “attract”. By designing and managing POPS, developers can attract the consumers who are essential to the success of their sites and who might be put off by a grubby council-managed square – or by a sterile shopping mall door.

A 2011 London Assembly Report found that the expansion of Canary Wharf in the 1990s was a turning point for developers who now “assume that they themselves will take ownership of an open space, with absolute control, in order to protect the value of the development as a whole”. In many ways this is a win-win situation; who doesn’t appreciate a nice water feature or shrub or whatever else big developer money can buy?

The caveat is, as academic Tridib Banerjee pointed out back in 2001: “The public is welcome as long as they are patrons of shops and restaurants, office workers, or clients of businesses located on the premises. But access to and use of the space is only a privilege and not a right” – hence the stories of security guards removing protesters or homeless people who threaten the aspirational appeal of places like Granary Square.

In the US, developers have taken this kind of space-curation even further, using public spaces as part of their formula for attracting the right kind of worker, as well as consumer, for nearby businesses. In Cincinnati, developer 3CDC transformed the notoriously crime-ridden Over-The-Rhine (OTR) neighbourhood into a young professional paradise. Pouring $47m into an initial make-over in 2010, 3CDC beautified parks and public space as well as private buildings.

To do so, the firm received $50 million  in funding from corporations like Procter and Gamble, whose Cincinnati headquarters sits to the South-West of OTR. This kind of hyper-gentrification has profoundly change the demographics of the neighbourhood – to the anger of many long-term residents – attracting, essentially, the kind of people who work at Procter and Gamble.

Elsewhere, in cities like Alpharetta, Georgia, 3CDC have taken their public space management even further, running events and entertainment designed to attract productive young people to otherwise dull neighbourhoods.

Data pools

The proposed partnership between the city of Toronto and Sidewalk Labs (owned by Google’s parent company Alphabet) has highlighted another motive for companies to own public space: the most modern of all resources, data.

Data collection is at the heart of the ‘smart city’ utopia: the idea that by turning public spaces and the people into them into a vast data pool, tech companies can find ways to improve transport, the environment and urban quality of life. If approved next year, Sidewalk would take over the mostly derelict east waterfront area, developing public and private space filled with sensors.

 Of course, this isn’t altruism. The Globe and Mail describe Sidewalk’s desired role as “the private garbage collectors of data”. It’s an apt phrase that reflects the merging of public service and private opportunity in Toronto’s future public space.

The data that Sidewalk could collect in Toronto would be used by Google in its commercial projects. Indeed, they’ve already done so in New York’s LinkNYC and London’s LinkUK. Kiosks installed around the cities provide the public with wifi and charging points, whilst monitoring traffic and pedestrians and generating data to feed into Google Maps.

The subway station at Hudson Yards, New York City. Image: Getty.

This is all pretty anodyne stuff. Data on how we move around public spaces is probably a small price to pay for more efficient transport information, and of course Sidewalk don’t own the areas around their Link Kiosks. But elsewhere companies’ plans to collect data in their POPS have sparked controversy. In New York’s Hudson Yards development – which Sidewalk also has a stake in – ambiguity over how visitors and residents can opt out of sharing their data when in its public square, have raised concerns over privacy.

In Toronto, Sidewalk have already offered to share their data with the city. However, Martin Kenney, researcher at the University of California at Davis and co-author of 2016’s ‘The Rise of the Platform Economy’, has warned that the potential value of a tech company collecting a community’s data should not be underestimated. “What’s really important is the deals Toronto cuts with Sidewalk may set terms and conditions for the rest of the world," he said after the announcement in October.

The project could crystallise all three motives behind the ownership of POPS. Alongside data collection, Sidewalk will likely have some leeway over planning regulations and will certainly tailor its public spaces to its ideal workers and consumers – Google have already announced that it would move its Canadian headquarters, from their current location in Downton Toronto, into the first pilot phase of the development.

Even if the Sidewalks Lab project never happens, the motives behind companies’ ownership of POPS tell us that cities’ public realms are of increasing interest to private hands.

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