Which city has the longest metro system?

Is Seoul the world's longest metro? Image: Getty.

This week we're taking a look at the surprisingly complicated question of which city has the largest metro in the world. As with so often with these things, the answer is: it depends how you count.

Yesterday we did number of stations. Today, we're measuring by route length.

You'd think, by restricting ourselves to a simple, one-dimensional numerical measure, that working out which city had the longest metro system in the world would be simple, wouldn't you?


Ha. No such luck. This time (spoilers), the root of the confusion lies in the vexed question of what counts as one metro network.

One oft-cited candidate for the world’s longest metro network is the one on Seoul, which only opened in 1974 but by 2013 included 987.5km of route on 18 lines. That's pretty much enough to get you from London to Marseille. No other city comes close.

So why is this question remotely contentious? Because it's surprisingly unclear whether that metro should be counted as one system or several. It includes lines 1-9, the subway proper, which is operated by the Seoul Metropolitan Rapid Transit Corporation and the Seoul Metro (with which it'll merge next year).

But it also includes routes run by national rail operator Korail. Most contentiously, it includes lines run by satellite cities, such as the Incheon Transit Corporation, which operates trains in, well, Incheon.

 

 

An extract from a map of Seoul's complete metro network created by Wikipedia User IRTC1015. You can see the terrifyingly complicated full version here.

All these operators provide a single integrated network – but it's still the equvialent of measuring the London Underground by counting Overground, DLR, and so forth, or of counting the RER and Transilien as part of the Paris Metro. We are in danger, in other words, of comparing apples and oranges.

So what if you try to stick to apples alone? Look at lines 1-9 alone, and the network measures only 311km.


Which is quite a lot smaller and probably not the biggest in the world at all.

Other candidates for the top slot can’t promise the 900km+ of route that the wider definitions of the Seoul metro do, but the figures they do cite are probably less contentious.

One is the Shanghai Metro, which runs to 548km and counting. In 2013, it achieved the distinction of becoming the first Chinese metro network to cross provincial boundaries, when line 11 was extended into the satellite city of Kunshan in neighbouring Jiangsu province.

There's talk of extending it further, to connect up with metro systems of the cities of Suzhou and Wuxi, both of which are 100km away or more, too. Not bad given that Shanghai didn't open its first metro line until 1993.

It isn't the only monster subway system that's sprouted in China recently either. The Beijing Subway, first opened in 1969, is the country's oldest, so it got a bit of a head start on Shanghai. Today, it runs 18 lines, serves 319 stations, and stretches for 527km.

Schematic map of Beijing's subway, created by Wikipedia Users Ran and Hat600.

This is another one of those networks which has more than one operator: this one's split between the state-owned Beijing Mass Transit Railway Operation Corp (15 lines) and the Beijing MTR Corp (a joint venture with the Hong Kong transit authorities, which operates three). Between them, in 2014, they carried 3.4bn passengers.

One interesting feature of Beijing's metro is its station names, which, translated literally, mean things like Smooth Justice, Heavenly Peace Gate and (less appealingly) Cholera Camp. So, there you go.

Here, best we can tell, with all the caveats about different cities playing by different rules here, is the top 10 of metros proper:

  • Shanghai Metro – 548km
  • Beijing Subway – 527km
  • London Underground – 402km
  • New York Subway – 373km
  • Seoul Subway – 332km
  • Moscow Metro – 328km
  • Madrid Metro – 294km
  • Guangzhou Metro – 240km
  • Mexico City Metro – 227km
  • Nanjing Metro – 224km

Tomorrow: we try to count passenger numbers and things get really complicated.

Research: Suren Prasad.

 
 
 
 

Covid-19 is highlighting cities' unequal access to green space

In the UK, Londoners are most likely to rely on their local park for green space, and have the best access to parks. (Leon Neal/Getty Images)

As coronavirus lockdowns ease, people are flooding back to parks – but not everyone has easy access to green space in their city.

Statistics from Google show that park attendance in countries across the globe has shot up as people have been allowed to move around their cities again.

This is especially true in urban areas, where densely populated neighbourhoods limit the size of private green space – meaning residents have to go to the park to get in touch with nature. Readers from England can use our interactive tool below to find out how much green space people have access to in their area, and how it compares to the rest of the country.

 

Prime Minister Boris Johnson’s announcement Monday that people are allowed to mingle in parks and gardens with groups of up to six people was partially following what people were doing already.

Data from mobile phones show people have been returning to parks across the UK, and also across Europe, as weather improves and lockdown eases.

People have been returning to parks across the world

Stay-at-home requirements were eased in Italy on 4 May, which led to a flood of people returning to parks.

France eased restrictions on 1 May, and the UK eased up slightly on 13 May, allowing people to sit down in public places so long as they remain socially distanced.

Other countries have seen park attendance rise without major easing of lockdown – including Canada, Spain, and the US (although states there have individual rules and some have eased restrictions).

In some countries, people never really stopped going to parks.

Authorities in the Netherlands and Germany were not as strict as other countries about their citizens visiting local parks during lockdown, while Sweden has famously been avoiding placing many restrictions on people’s daily lives.


There is a growing body of evidence to suggest that access to green space has major benefits for public health.

A recent study by researchers at the University of Exeter found that spending time in the garden is linked to similar benefits for health and wellbeing as living in wealthy areas.

People with access to a private garden also had higher psychological wellbeing, and those with an outdoor space such as a yard were more likely to meet physical activity guidelines than those without access to outdoor space. 

Separate UK research has found that living with a regular view of a green space provides health benefits worth £300 per person per year.

Access is not shared equally, however, which has important implications for equality under lockdown, and the spread of disease.

Statistics from the UK show that one in eight households has no garden, making access to parks more important.

There is a geographic inequality here. Londoners, who have the least access to private gardens, are most likely to rely on their local park for green space, and have the best access to parks. 

However the high population in the capital means that on the whole, green space per person is lower – an issue for people living in densely populated cities everywhere.

There is also an occupational inequality.

Those on low pay – including in what are statistically classed as “semi-skilled” and “unskilled” manual occupations, casual workers and those who are unemployed – are almost three times as likely as those in managerial, administrative, professional occupations to be without a garden, meaning they rely more heavily on their local park.

Britain’s parks and fields are also at significant risk of development, according to new research by the Fields in Trust charity, which shows the number of people living further than a 10-minute walk from a public park rising by 5% over the next five years. That loss of green spaces is likely to impact disadvantaged communities the most, the researchers say.

This is borne out by looking at the parts of the country that have private gardens.

The least deprived areas have the largest gardens

Though the relationship is not crystal clear, it shows at the top end: Those living in the least deprived areas have the largest private green space.

Although the risk of catching coronavirus is lower outdoors, spending time in parks among other people is undoubtedly more risky when it comes to transmitting or catching the virus than spending time in your own outdoor space. 

Access to green space is therefore another example – along with the ability to work from home and death rates – of how the burden of the pandemic has not been equally shouldered by all.

Michael Goodier is a data reporter at New Statesman Media Group, and Josh Rayman is a graphics and data visualisation developer at New Statesman Media Group.