zlacker

I cannot stop thinking about the fact that air travel wastes so much energy, just to float. Buoyancy is free.

It is insane that we are not doing materials research on how to capture vacuum in thin cavities.

>>whatev+(OP)
Modern jetliners get a higher miles per gallon per seat than most US (ICE) cars. They easily beat any ICE car with a single occupant in miles per gallon equivalent. If you want to minimise fuel usage and can't find someone to share with, it's better to fly! The issue is almost entirely the distance travelled.

>>SPICLK+t4
Cars also waste energy just to overcome friction while most of the times they do not change momentum (go straight at constant speed). But this is a discussion for another tire.

>>whatev+s6
Aerodynamic drag accounts for more energy losses than tyre friction (and tyre friction can be relatively easily changed with tyre pressure or tyre type).

>>SPICLK+t4
now do high speed rail..

>>riirif+No
It varies so much depending on passenger occupancy rates. Planes tend to run near 100%, and cars (at least in the US, although I'm sure other countries aren't much better) at near 20%.

Assuming 1mpg for the entire train, it needs at least 100 passengers to compare to a fully-occupied passenger plane.

>>SPICLK+Yp
Can you name a HSR route that exists between US cities that would challenge the near 100% occupancy rates? Seems relevant. We probably need to compare routes where there exists air travel and HSR to draw any occupancy rate choices, but this is clearly an aside.

The point is that it makes air travel ludicrous from an energy perspective where rail at high speeds (200mph) is possible

>>ririfd+Br
Edit: Now you've clarified your question.

There's nothing special about HSR when considering fuel (or energy) efficiency, except that it's probably less efficient over all due to increased air drag, and that it needs very particular infrastructure and passenger demand to make it work.

I'd hazard a guess that many (most?) flight routes are nowhere near popular enough to make them viable for train replacement.

Eg. The bullet train in Japan has a peak capacity of over 20,000 passengers per hour.

The most popular flight route in the US has around 3 million passengers per year, or ~340 an hour.

>>ririfd+Br
Air travel is SO inefficient that it ONLY makes sense to fly with a full plane.

Train travel is so efficient that running nearly empty trains is just accepted.

>>bombca+ov
You're joking, right?

Passenger capacity is part of the design of air travel. Even so, a plane could be at 1/3rd capacity before it's less efficient than a singly-occupied car.

Trains are largely a relic of the Industrial Revolution - except for those places where population distribution has made it feasible to invest in specialised passenger rail, the degree of infrastructure investment required makes them economically infeasible given a blank slate today.

If we were really concerned about transport efficiency, long-distance bus routes are the answer. Per-seat energy usage is comparable to trains, but with a fraction of the infrastructure cost, and significantly more flexibility. Countries that have a blank slate and are only interested in maximum transport for minimum cost (ie, the developing world) have gone that way for a reason.

We accept nearly empty trains, despite them needing at least 30 passengers to be competitive from a fuel efficiency standpoint with a singly-occupied car, because trains are largely seen as a service. Very few passenger trains are economically viable without government support.

>>SPICLK+Tw
There’s an irony where tech folks use a forum to discuss ideas, amongst which involve Generative Language Models which aid and abet political astroturf campaigns that make ridiculous arguments to waste people’s energy when they use tech forums…

It’s like a drain and the usefulness of the forum is swirling around and largely depleted

The interesting problem for tomorrow’s internet is how to automatically root out this nonsense. That’s a browser addin / AI tool that would be useful. Take the comments and probabilistically score the nonsense factor. A new PageRank if you will.

The value is in the well trained bullshit detector. One that could have read the parent comment on everyone’s behalf and saved us all the bother.

Let the corporate/pr/oil industry shills exist in their own space, and enable legitimate discussion to continue

>>ririfd+yE
You need to state your premise to enable a reasonable discussion. I've been talking about energy or fuel efficency when it comes to public transport (I see you don't have any return for this, because the facts are indesputible).

However, your premise is that "people must use (I assume, electrified) HSR to stop burning oil". This is an entirely different discussion. In many ways, it is significantly less efficient when looking purely at an energy usage perspective, especially when considering new routes across sparsely-populated expanses with relatively low demand.