4 ms·
>5-minute walkable neighborhoods. The proximity to services of cities combined with the roominess of suburbs. At least in theory it's the perfect place to live.
by scythe 4y ago
>5-minute walkable neighborhoods. The proximity to services of cities combined with the roominess of suburbs. At least in theory it's the perfect place to live.
The problem with 175 km of continuous "subway" is that you probably don't want to walk more than 2.5 km to the train (if that, it's Arabian hot) so you have 35 stops (5 km apart) along the line at a minimum — with a blistering acceleration of g = 10 m/s^2 you're stuck at an average velocity of 18 km/h, so it's eleven hours of travel end-to-end assuming two minutes at each stop. Those are optimistic assumptions. You can mitigate it slightly by having express trains skip stops, but now it gets complicated, etc. To be anywhere near reasonable you probably want about five actual transit lines on the single "line".
A much less crazy plan would have 8-16 compact neighborhoods at various spacings along the line, where you can get the most out of the directional freedom of walking, and the train can go much faster without having so many stops.
- londgine 4y agoimagine train lines that stop at prime number stations. so line 2 would stop at station 2,4,6 like 3 would stop at 3,6,9. if you want to get to station 10 you could take line 11 directly to station 11 and then line 1 back. alternatively, you could use an app to calculate the best route based on when you arrived
- everforward 4y agoThat probably depends on how many rails and when trains can cross onto other rails. I.e. a basic flow is all trains go one direction on one rail, and they all go backwards on the other. You can use the "wrong direction" rail to pass another train, but only if there's no oncoming train. Waiting for a train to go through so you can cross is effectively the same as stopping at a station. The answer is to have more rails, but that takes more space, and I'm not sure how much space they're dedicating to the rail system. Rail scheduling is fascinating; it does make me curious how fast they can make this system in a real world environment.
- satyrnein 4y agoThe video says it's 20 minutes end to end, somehow.
- scythe 4y agoThe numbers in my post have some significant errors — I mashed it in just before my plane was taking off — but the argument is one I have seen carried out more carefully elsewhere. 175 km in 20 minutes would be roughly the top speed of the fastest train ever built. I'm doubting that.
- hansword 4y agoWith an express train from the easternmost stop to the westernmost stop, zero in-between stops... possible, but not very practicable.
- unethical_ban 4y agoA train system wouldn't have to stop at every neighborhood linearly. They could optimize for connections.