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Comment by esnowrackley | Hacker News Reader

> An underground train network is the pinnacle of public transport—right now, in New York and Chicago... people are being whisked through a network of tunnels, deep below the bustling city

Chicago is almost entirely above ground. Very little of the network is below the city.

Out of 224.1 miles of track, only 11.4 are underground (5%).[1] Only two out of the eight lines run that 11.4 miles and the majority of their time is spent on elevated tracks above street level.

That said, a ring around the city would be great. The hub and spoke layout dramatically limits Chicagoans ability to get around.

[1]: https://www.transitchicago.com/facts/

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Despite its name, only 45% of London Underground is underground. As I recall only 3 or 4 lines are entirely subterranean, most run on the surface once they are out of the centre.

Imagine what London would be like with the majority of the lines in the centre being on elevated tracks instead of underground

A previously beautiful city, now ruined by train tracks everywhere?

You’re 140 years too late.

Tokyo has tons of above ground tracks and it’s fine. One big problem in american cities is that train tracks are built too high off the ground and aren’t human scale.

Paris has line 6 crossing it entirely and running right next to some very touristy places and it’s overall beautiful. Aerial lines don’t have to be eyesore.

I can see and hear the Overground from my kitchen window, I honestly think it makes the city more beautiful.

The first thing that sprang to mind was the movie Metropolis.

Also, Wuppertal.

South of the Thames has a fair bit of elevated rail.

Even zone one does for the normal rail system, but I was imagining what it would be like with the deep lines elevated.

Only 2 lines are entirely underground - Waterloo and city (literally two stops) and Victoria (the Victoria depot is above ground but all casement services are below ground)

Precisely because of the name, it shouldn't have been hard to notice that the Chicago "El" is elevated. The "Loop" is entirely above ground and gives downtown Chicago its primary identity.

edit: we do desperately need a circle line, or failing that, dedicated bus lanes imitating one. Instead we get less and less service every year since the year they decimated "owl" (night) service.

> people are being whisked through a network of tunnels, deep below the bustling city

Also compared to London or many metro systems, Chicago’s is not deep underground at all. As a Chicagoan I was very surprised the first time I saw some of the escalators in London or Washington.

In some parts Chicago’s is almost literally just basement level with nearby buildings.

How did they build those deep tunnels before the invention of TBMs? It must have been slow going.

Get some people down there with shovels and carts, same as any public works project earlier than ~1720.

There was already a big coal mining industry so I assume they'd have used those techniques.

>How did they build those deep tunnels before the invention of TBMs?

Same approach as TBMs just manual AF. Dig a bit, put in supporting structure. Rinse and repeat.

They've been at it since 1890 though so that helps

The scenario suitable for TBM is surprisingly limited so even nowadays many tunnels are still dig using the good’o way, mostly with explosives

??? explosives? in mud? (well, clay)?!

tunnels are bored depending on the soil, length, diameter. Most projects I have seen use TBMs and the New Austrian Tunneling Method. Explosives are quite the minority (not many tunnels are in solid rock), even the Gotthard tunnels were dug with TBMs

If you have access there is a fascinating program on BBC iPlayer about digging the Victoria Line in the sixties. It's not all manual work but a surprising amount still is.

https://www.bbc.co.uk/iplayer/episode/p00sc29t/how-they-dug-...

The big innovation for the Underground was the tunneling shield. It kept the tunnel from collapsing and has places for people to dig out the face.

The reason that the Underground uses small tunnels was because expensive even then to pay people to dig out tunnels by hand.

Chicago works like most American metros.

Designed to get you downtown or out of downtown.

Let's say you're in Lakeview and need to get to O'Hare.

It often can be easier to Uber downtown and then ride the Blue line to O'Hare vs Red line to Blue line.

Given how expensive new metro lines are, a few express busses could do wonders.

Even just a dedicated bus lane can work.

It’s been a bit since I’ve lived in Chicago - weren’t they adding dedicated bus lanes to Ashland? I remember them doing that in and near the loop as well on Washington and maybe Monroe?

>a ring around the city would be great.

It's so obvious that a ring around the city train is pinnacle of urban transport similar to London Circle line and Tokyo Yamanpte line, and every city and metropolis should has one of them.

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