The whole idea of a linear city is daft. A circle is way more efficient at getting around. The dimensions of the Line are, of course, silly as well.
There are much more effective ways to achieve population control than building line cities and moving people into them.
But only with a line can you be aligned with your ruler's dreams.
Curved tracks do mean limits on top speed, as the centrifugal force needs to be kept below what would be uncomfortable for passengers. It also can cause some issues for building stations, as curved stations require a wider gap between the train and the platform. But neither is a blocking issue, all train tracks in the world do have curve, and curved stations aren't unusual in public transport systems.
The grandparent probably means disk, not ring-shaped when mentioning circles anyway. Pick any 2 point at random into a 33km² circle, the average distance will be 4km, and worst case scenario 6km. Do the same thing in a 33km², 200m-wide "line", the average distance will be 85km, with a worst case of 170km. A circular city doesn't need nearly as much raw speed for it's public transport to be more efficient than transport in a nonsensical linear city could ever be, even if you throw in ridiculously fast trains and sprinkle magical AI thinking.
It's not a coincidence that all major cities are roughly circular even though they are built around roughly linear features (navigable rivers and/or coast line). It's just what naturally works.
In a regular city that grows outwards, you'd expect there to be circumferential routes as well as cross-city routes connecting various points, making the travel time more bearable.
With no top speed, accelerate for 85km at 1m/s then decelerate for the next 85km/s at 1m/s and that's about 13 minutes with a top speed of about 900mph. 1m/s is the top acceleration you can have for a typical passenger train for comfort purposes.
Total area of a 170km*200m city is 34 square km, or a city about 6.5km across.
London's Elizabeth line (crossrail) covers a distance of 6.75km from Paddington to Liverpool Street in 11 minutes, with 3 intermediate stops.
The circumference of a 6.5km diameter city would be 20km. 20 cross-city lines with decent headway and interchange would give a worst case journey of
- 250m to nearest station - 3 minutes walk
- 2 minute wait for train
- 5 minutes to central station
- 200m/3 minutes to appropiate platform
- 2 minute wait for train
- 5 minutes to destination station
- 200m/3 minutes to destination
25 minutes. From anywhere to anywhere.
And you can still build mostly straight-line trams in a circle anyway.
To get the same area, you'd have to have slightly more center-line circumference on a ring city as linear distance on a line, but even so your transit distances are going to be shorter on the ring.
I guess I don’t really understand the criticism, most of which seems to be “you should just build something that isn’t the thing you want to build.” There is plenty of aesthetic merit to the linear city idea on its own.
To use an example of a place that already exists: the city Łódź in Poland is situated along a single linear 4-5km street. Other neighborhoods branch off from it, but essentially the main road is the city’s layout. I really like it and think it’s a lot more interesting than it would be as a circle, even if the transit is theoretically not as optimal. There is something very aesthetically appealing about it.
Are we just making things up? Just by a single glance at a map of Łódź you can see that this is not true. The city is clearly blob shaped.
> I guess I don’t really understand the criticism, most of which seems to be “you should just build something that isn’t the thing you want to build.”
The criticism is that there are reasons why cities are built the way they are built. "Looks good on a 3d render" is not a great reason to do something, and the reasons the proponents list don't hold up to scrutiny.
https://en.wikipedia.org/wiki/Piotrkowska_Street
And yes, as I wrote, it is the main axis of the city, even if other neighborhoods branch off of it. This is a basic obvious fact about the city:
From the very beginning this street was the central axis, around which the city grew bigger, and its development spontaneously gave the present shape to its centre. At first the city was mainly the highway, but later it changed into the city's showcase, the leisure and shopping centre, where the life of growing industrial agglomeration could be observed.
What the sentence you are quoting claims is that this is the street the city grow out of. Which is a different statement than saying that the one you said. The "the city Łódź in Poland is situated along a single linear 4-5km street" describe the appearance and layout of the city today, the quote you are quoting describe the history of the city and in which order it was built out.
You can’t tell what it is on a map because you wouldn’t expect a pedestrianized street to be 100m wide. But I assure you, it is the busiest street and has the most foot traffic and commercial activity.
This argument is such a waste of time. I’ve been there, you’ve spent five minutes looking at Google maps. I brought it up as an example of a city designed around a straight line. Which it is.
Go waste someone else’s time.
Then it's Goodhart law in action. A fast transit system is desirable because it's a proxy for low-friction travel. This has the speed and the friction.
Piotrkowska?
You'd spend a lot of time on that one train line though - and I imagine in the central bits it would get really really busy as people are trying to get to the other end. And what happens if that train line breaks?
Making a city circular takes advantage of geometry - even at the cost of having to build more than one train line. It also opens up the possibility of other forms of travel - buses, bikes, cars.
It doesn't surprise me that this is starting to fall apart. When it was announced it seemed completely unhinged.
Probably because it looks cool in CGI renderings and nobody else has one, for reasons that are probably becoming apparent to all involved.
Meanwhile if you design a disc city, you can keep expanding outwards, but that's going to be increasingly far from the center. It's going to be very difficult to build a new airport into a middle of the city (if such needs arises), meanwhile it's much easier to do that for the middle segment of a linear city.
This is applying the terrible thinking that gives us micro service hell to city planning.
I think your argumentation rests on this, but you should explain why it's daft and how it makes people's lives miserable. I would personally enjoy having 20 minute access to any place in the city I live (which is far from having 9 million people) and still have a vast open space nearby.
For example - if there is a natural element like a river, lake, canyon, etc. that you want to maximize city exposure to. A linear city roughly following the Grand Canyon would be infinitely more interesting than a circular one situated at one end of it.
So, basically a regular city.
By using a line they can just shut off one part of the line from the rest with one or two cuts.
a) So you have people living uniformly distributed on a line of length 1. When you pick 2 at random, what's the average distance from one to the other?
b) How about if they live on a circle of circumference 1 (and you can only travel along the circumference)?
c) How about if they live on a disk of circumference 1 (and you can travel straight across the disk)?