211–220 of 237 posts
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Guys, guys, hear me out. I have a crazy idea. What if we use special cars only for the tunnel with some kind of ride sharing system? and then we put the cars on rails? This keeps them on track and also the rolling friction is much lower. Also, we could continuously charge the battery of the car if we have some kind of wire going alongside the tunnel and a slip contact. Actually we could make the cars much bigger as w…
If you can figure out how to let people transport their vehicles through your tunnel without your car having to make scheduled stops, or follow a single path then you've got a business.
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Right, but 15 SUVs 5s apart carry 105 people, and if they can actually travel at an average 150mph, that's faster than the average speed of Skytrain's fastest line by another 3x — so, now we're looking at 315 people moved through the space at the same time. Factor in cost advantages of the tunnel — 4x cheaper mile-for-mile for the prototype, it seems like? — and the same dollars spent on Boring Co tunnels could actua…
>15 SUVs, Travelling 150 mph, a second apart You're fond of throwing in a lot of utterly implausible figures to support your argument here
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Somehow you assume they will be able to get into that tunnel at these intervals
haha yep. This plan is like when a city widens a highway but doesn't touch other parts of the road network? What happens? It just moves the choke point somewhere else in the network.
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> Never heard of horizontal scaling? My SO is a soils engineer/geo-physicist, so I know a bit about the issues at play, mostly over dinner conversations. When it comes to large infrastructure projects like these, the problems are multitude and all very individual, especially in such a geologically active zone as the LA Basin [0]. Though Musk et al. should be congratulated for the incredible achievement of even trying…
> My SO is a soils engineer/geo-physicist, so I know a bit about the issues at play what's this? PhD by association? I came to Bay Area from Japan, I was surprised to hear that high buildings are not a thing here because of earthquakes. For comparison, in Japan there are about 2000 earthquakes that person can feel every year. And somehow monorail/high-speed trains/tunnels/skyscrapers are everywhere. Lazy engineering…
>what's this? PhD by association?
I mean, I did day that I only know a bit about it.
That said, there are differences in the dynamics of the soil between Japan and California; each situation is unique. When it comes to earthquakes, Japan typically has deeper earthquakes due to the subduction zone that it sits above and the earthquakes are compressional(very roughly), while in CA, the earthquakes tend to be shallower along the San Andreas and more strike-slip (again, very roughly) up to 30km down involving mostly the crust. In general, one should not expect that buildings in two different seismic zones should be similar.
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No, for a battery fire it's quite the opposite. It's going to release all of that stored energy and burn up the electrolyte one way or another. Flooding it with water is the best way to deal with all of that energy.
Releasing highly flammable hydrogen gas is definitely not "dealing with the energy". Both electrolysis and the reaction of water with lithium release plenty of it.
As to the notion that there's lithium metal in the batteries that could react with the water, you're thinking of non-rechargeable lithium batteries. Lithium ion cells use a lithium compound, not just pure elemental lithium. The formulation might be something like LiFePO4 but the point here is that it's not just lithium metal sitting around inside of it.
Also Tesla has an emergency response guide that includes instructions on fighting a battery fire. It's on page 22 (23 of the PDF) and it makes it clear that you want to douse the thing in as much water as possible and keep dousing it until it's totally gone. Tons of water is exactly what's called for when fighting these kind of fires.
https://www.tesla.com/sites/default/files/downloads/2016_Mod...
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I'm not sure what you're purporting to show other than two people disagreeing with each other, without providing evidence... Sure, an individual subway car has "more capacity," but does a subway system have more capacity? For example, I rarely see BART trains come within five minutes of each other. A tunnel that allows cars within 10 seconds of each other could provide more capacity than a tunnel with higher-density…
Peak headtimes on BART are a train every 2-3 minutes, with trains carrying up to 1400 people (let's call it 1000 for the sake of argument). So at the low end, that's around 20,000 people an hour. If you had cars with a headway of 5 seconds then that's 1200 cars an hour, so you'd need an average occupancy of over 16 people per car. That's unrealistic, so yes, a subway tunnel has more capacity.
If you could bore 4x the tunnels, you'd need a capacity of 4 people per car to match peak BART. And... hey, that describes pretty much every car in existence. But using the BART comparison: recent estimates [1] put each additional mile of BART track at over $1 billion. So if it really costs $10MM/mile for the Boring Co, you could bore 32x the tunnels and beat BART capacity by a factor of two assuming even single occupancy vehicles, at about a third of the cost.
[1]: https://sf.curbed.com/2018/6/18/17464616/bay-area-subway-tra...
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> Never heard of horizontal scaling? My SO is a soils engineer/geo-physicist, so I know a bit about the issues at play, mostly over dinner conversations. When it comes to large infrastructure projects like these, the problems are multitude and all very individual, especially in such a geologically active zone as the LA Basin [0]. Though Musk et al. should be congratulated for the incredible achievement of even trying…
> My SO is a soils engineer/geo-physicist, so I know a bit about the issues at play what's this? PhD by association? I came to Bay Area from Japan, I was surprised to hear that high buildings are not a thing here because of earthquakes. For comparison, in Japan there are about 2000 earthquakes that person can feel every year. And somehow monorail/high-speed trains/tunnels/skyscrapers are everywhere. Lazy engineering…
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I've not seen anything that would suggest either ratio.
So what's your guess?