Author Topic: Elon The Boring Company  (Read 157171 times)

Online QuantumG

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Re: Elon The Boring Company
« Reply #800 on: 12/04/2017 11:43 PM »
Elon isn't even sold on rails.
Jeff Bezos has billions to spend on rockets and can go at whatever pace he likes! Wow! What pace is he going at? Well... have you heard of Zeno's paradox?

Online Lar

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Re: Elon The Boring Company
« Reply #801 on: 12/05/2017 02:14 AM »
To make the system versatile and maximize commonality with Tesla products, vehicles need to be self-contained (internal batteries).  Getting power from a hot rail or similar device while traveling at high speeds and changing lanes to merge and exit will not have much benefit to offset its disadvantages.  The days of overhead line powered urban trolleys and light rail is hopefully near an end, too.
I would expect a hybrid system... batteries but also power contacts.. perhaps auto recharging while waiting for next fare, or perhaps contacting in the tunnel in motion when it is easy and safe (straight stretches that are not too high speed) or maybe even induction power transfer?
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Online nacnud

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Re: Elon The Boring Company
« Reply #802 on: 12/05/2017 03:47 AM »
Induction charging seems a plausible system for the tunnels.


Online Jdeshetler

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Re: Elon The Boring Company
« Reply #803 on: 12/05/2017 05:11 AM »
Agreed, it will be railess.  Here is what I see.

A highly autonomous skate that:
 - outnumber the EV cars, just like Yellow Taxis in NYC, maybe the same color?
 - never leaves the elevator at the ground surface.
 - instruct the EV car to lock the doors & windows during moving so it can't be open except in an extreme case.
 - goes everywhere inside the tubes.
 - pull out from the service to the nearest underground recharging stations when need.
 - will not come to pick up specific car if their destination is greater than the range of the skate's current battery.
 - provide charging to EV car while traveling thus reduce the need for above ground charging stations in high density locations (if skate's internal battery is over-capacity).
 - always knows the locations of other skates in real time.
 - take other tubes for bypassing at the last minute, never slow down at all.
 - can replace tires w/ single hub nuts at any underground unmanned service stations at interval time.
 - the odd of breakdown is very low since each axle will have it's own motor (Model 3's) with dual battery modules.

Offline ppb

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Re: Elon The Boring Company
« Reply #804 on: 12/05/2017 05:32 AM »
Agreed, it will be railess.  Here is what I see.

A highly autonomous skate that:
 - outnumber the EV cars, just like Yellow Taxis in NYC, maybe the same color?
 - never leaves the elevator at the ground surface.
 - instruct the EV car to lock the doors & windows during moving so it can't be open except in an extreme case.
 - goes everywhere inside the tubes.
 - pull out from the service to the nearest underground recharging stations when need.
 - will not come to pick up specific car if their destination is greater than the range of the skate's current battery.
 - provide charging to EV car while traveling thus reduce the need for above ground charging stations in high density locations (if skate's internal battery is over-capacity).
 - always knows the locations of other skates in real time.
 - take other tubes for bypassing at the last minute, never slow down at all.
 - can replace tires w/ single hub nuts at any underground unmanned service stations at interval time.
 - the odd of breakdown is very low since each axle will have it's own motor (Model 3's) with dual battery modules.
Sounds great, but what about the fire hazard from high energy density batteries in a tunnel?
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Offline woods170

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Re: Elon The Boring Company
« Reply #805 on: 12/05/2017 07:16 AM »
Agreed, it will be railess.  Here is what I see.

A highly autonomous skate that:
 - outnumber the EV cars, just like Yellow Taxis in NYC, maybe the same color?
 - never leaves the elevator at the ground surface.
 - instruct the EV car to lock the doors & windows during moving so it can't be open except in an extreme case.
 - goes everywhere inside the tubes.
 - pull out from the service to the nearest underground recharging stations when need.
 - will not come to pick up specific car if their destination is greater than the range of the skate's current battery.
 - provide charging to EV car while traveling thus reduce the need for above ground charging stations in high density locations (if skate's internal battery is over-capacity).
 - always knows the locations of other skates in real time.
 - take other tubes for bypassing at the last minute, never slow down at all.
 - can replace tires w/ single hub nuts at any underground unmanned service stations at interval time.
 - the odd of breakdown is very low since each axle will have it's own motor (Model 3's) with dual battery modules.
Sounds great, but what about the fire hazard from high energy density batteries in a tunnel?
No different from the fire hazard from any other form of providing energy to the skate.
By definition: fire in a tunnel is bad.

Offline speedevil

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Re: Elon The Boring Company
« Reply #806 on: 12/05/2017 11:27 AM »
Sounds great, but what about the fire hazard from high energy density batteries in a tunnel?
The fire hazard can be sharply reduced by adding inert material to the battery, such that it can safely contain small failures until it gets out of the tunnel.
On detecting a failure internally, the car hooks up with the next car to push/pull it, and continues otherwise as normal.
Only if the failure begins to propagate does the traffic in the tunnel slow and move away from it, potentially changing tunnels or terminating early.
If the vehicle comes to an uncontrolled stop, slow firefighting vehicles mounted to the tunnel roof spaced every few hundred meters trundle up to it at 20mph or so, and deal with it.
This is really a very different case from tunnel fires of the past, which have often involved many tons of concentrated uncontrolled fuel (margerine, for example)

Offline starsilk

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Re: Elon The Boring Company
« Reply #807 on: 12/05/2017 03:23 PM »
Agreed, it will be railess.  Here is what I see.

A highly autonomous skate that:
 - outnumber the EV cars, just like Yellow Taxis in NYC, maybe the same color?
 - never leaves the elevator at the ground surface.
 - instruct the EV car to lock the doors & windows during moving so it can't be open except in an extreme case.
 - goes everywhere inside the tubes.
 - pull out from the service to the nearest underground recharging stations when need.
 - will not come to pick up specific car if their destination is greater than the range of the skate's current battery.
 - provide charging to EV car while traveling thus reduce the need for above ground charging stations in high density locations (if skate's internal battery is over-capacity).
 - always knows the locations of other skates in real time.
 - take other tubes for bypassing at the last minute, never slow down at all.
 - can replace tires w/ single hub nuts at any underground unmanned service stations at interval time.
 - the odd of breakdown is very low since each axle will have it's own motor (Model 3's) with dual battery modules.
Sounds great, but what about the fire hazard from high energy density batteries in a tunnel?

also, tires leave rubber dust as they wear. (tire) rubber is flammable because of the oil content.

that means tunnels have to be cleaned regularly.

Offline JamesH65

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Re: Elon The Boring Company
« Reply #808 on: 12/05/2017 07:58 PM »
Agreed, it will be railess.  Here is what I see.

A highly autonomous skate that:
 - outnumber the EV cars, just like Yellow Taxis in NYC, maybe the same color?
 - never leaves the elevator at the ground surface.
 - instruct the EV car to lock the doors & windows during moving so it can't be open except in an extreme case.
 - goes everywhere inside the tubes.
 - pull out from the service to the nearest underground recharging stations when need.
 - will not come to pick up specific car if their destination is greater than the range of the skate's current battery.
 - provide charging to EV car while traveling thus reduce the need for above ground charging stations in high density locations (if skate's internal battery is over-capacity).
 - always knows the locations of other skates in real time.
 - take other tubes for bypassing at the last minute, never slow down at all.
 - can replace tires w/ single hub nuts at any underground unmanned service stations at interval time.
 - the odd of breakdown is very low since each axle will have it's own motor (Model 3's) with dual battery modules.
Sounds great, but what about the fire hazard from high energy density batteries in a tunnel?

also, tires leave rubber dust as they wear. (tire) rubber is flammable because of the oil content.

that means tunnels have to be cleaned regularly.

Looking at the guided bus system we have near us, that is never cleaned except by rain - very little dust on it even after drought periods. Can't see vacuuming the tunnel once a year being an issue.

Online QuantumG

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Re: Elon The Boring Company
« Reply #809 on: 12/05/2017 08:46 PM »
I don't see the point of inductive charging... it's pretty lossy. Just have plug-in charging stations for the skates. You could stack them one on top of the other.

Jeff Bezos has billions to spend on rockets and can go at whatever pace he likes! Wow! What pace is he going at? Well... have you heard of Zeno's paradox?

Offline rsdavis9

Re: Elon The Boring Company
« Reply #810 on: 12/05/2017 10:06 PM »
requires more skates to sit still for a while. But I agree with you the improved efficiency is probably more important.
With ELV best efficiency was the paradigm. The new paradigm is reusable, good enough, and commonality of design.
Same engines. Design once. Same vehicle. Design once. Reusable. Build once.

Online QuantumG

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Re: Elon The Boring Company
« Reply #811 on: 12/05/2017 10:23 PM »
... and it's not like the passenger pods would have to be idle, just swap the discharged skate for a fresh one. That's the brilliance of the skate concept.

Jeff Bezos has billions to spend on rockets and can go at whatever pace he likes! Wow! What pace is he going at? Well... have you heard of Zeno's paradox?

Offline AncientU

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Re: Elon The Boring Company
« Reply #812 on: 12/05/2017 10:50 PM »
requires more skates to sit still for a while. But I agree with you the improved efficiency is probably more important.

A few hundred mile range should nicely cover a day's runs.  Recharge overnight or between busy times (Yes, I know... there are no not busy times in LA).
« Last Edit: 12/06/2017 12:37 PM by AncientU »
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Offline docmordrid

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Re: Elon The Boring Company
« Reply #813 on: 12/06/2017 12:43 AM »
Detroit's QLine trolleys only rapid-charge when they're within a half mile or so of a depot, the rest of the time they're on battery power. I can see distributed runtime charging being useful for Loop as well.

(Detroit? Trolleys? The old town is changing, and fast.)
« Last Edit: 12/06/2017 12:49 AM by docmordrid »
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Offline Ludus

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Re: Elon The Boring Company
« Reply #814 on: 12/06/2017 02:49 PM »
I don't see the point of inductive charging... it's pretty lossy. Just have plug-in charging stations for the skates. You could stack them one on top of the other.

Current Tesla battery tech canít sustain 120-150mph speeds and rapid acceleration. It just draws too much power. Some method of providing most of the power from the roadbed is necessary for a system that has these specs and uses Teslaís powertrain.

Offline speedevil

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Re: Elon The Boring Company
« Reply #815 on: 12/06/2017 03:17 PM »
Current Tesla battery tech canít sustain 120-150mph speeds and rapid acceleration. It just draws too much power.

'Rapid' acceleration for a transit vehicle is not 0-120 in 14 seconds. (Tesla P85D).

Online Jdeshetler

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Re: Elon The Boring Company
« Reply #816 on: 12/06/2017 03:47 PM »
Imagine this, the skate is the "Horizontal Elevator" but without walls and use mild acceleration that fall within "very comfort zone" just like high speed vertical elevator in very tall buildings. So the underground tube is basically a rail-free horizontal elevator shaft.

Offline Zed_Noir

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Re: Elon The Boring Company
« Reply #817 on: 12/06/2017 04:03 PM »
Current Tesla battery tech canít sustain 120-150mph speeds and rapid acceleration. It just draws too much power.

Nah. Just hook one Model-3 battery pack to one motor connected to one wheel hub. Put 4 such assemblies on a skate than the 120 mph sustain speed seems doable. That is what Tesla did with the Semi-truck with more batteries storage for propulsion.

Offline CapitalistOppressor

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Re: Elon The Boring Company
« Reply #818 on: 12/06/2017 04:04 PM »
Current Tesla battery tech canít sustain 120-150mph speeds and rapid acceleration. It just draws too much power.

'Rapid' acceleration for a transit vehicle is not 0-120 in 14 seconds. (Tesla P85D).

Yeah, but your range is going to be sharply reduced even with acceleration being somewhat less than the maximum possible.

A related problem is that financial losses from depreciation will likely be increased by using batteries, which will wear out quicker than equivalent batteries on consumer vehicles due to deeper and more frequent charge/discharge cycles.

This can be countered with different chemistry and oversizing the batteries, but that increases capital costs.  I'm open to the idea that using batteries benefits Tesla as a whole by allowing them to benefit even more from scaling battery production, but hardwiring power into the tunnels just seems like it would be simpler and cheaper in the long run.

Arguments about the fire risk of batteries operating in these conditions is somewhat overblown.  Cascade failures are mostly caused by physical deformation/intrusions in the pack (from an accident) that should be rare in these conditions. A cascade failure that starts from an internal fault is a relatively slowly developing process that normally would allow time for the skate to be diverted and evacuated.

If there was some theoretical reason why the fire risk in the tunnels was unacceptable, Tesla could use intumescent coatings and cell components to slow and even shut down cascades.  They don't do this in their consumer packs (probably because of cost) but its always been an option for them.

Offline biosehnsucht

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Re: Elon The Boring Company
« Reply #819 on: 12/06/2017 09:24 PM »
If there was some theoretical reason why the fire risk in the tunnels was unacceptable, Tesla could use intumescent coatings and cell components to slow and even shut down cascades.  They don't do this in their consumer packs (probably because of cost) but its always been an option for them.

As I understand it they already use intumescent goo in their packs for retarding the spread of fire / thermal runaway. Unless they've stopped doing that?

(just ctrl-f intumescent)

https://www.greencarreports.com/news/1084682_what-goes-into-a-tesla-model-s-battery--and-what-it-may-cost

http://www.teslaupdates.co/2016/07/tesla-model-s-x-battery-pack-explained.html