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Rail has much higher initial and fixed costs than air travel, and high-speed trains consume more energy than aircraft on long-distance routes (as airliners trav
by nickff 6y ago
Rail has much higher initial and fixed costs than air travel, and high-speed trains consume more energy than aircraft on long-distance routes (as airliners travel at high altitude with low air resistance).
The literal footprint of a rail system is also very large; clearing and grading rail lines across the country would have a significant environmental impact.
- turnsnake55 6y agoThey can be electric and carry far more people than airplanes. There is no comparison. Planes are worse.
- iso947 6y agoThat’s a bold Claim. What proof do you offer?
- nickff 6y agohttps://en.wikipedia.org/wiki/California_High-Speed_Rail https://en.wikipedia.org/wiki/California_High-Speed_Rail for the costs side. https://www.grc.nasa.gov/www/k-12/airplane/drageq.html https://www.grc.nasa.gov/www/k-12/airplane/drageq.html for the drag side. There are also a huge number of fuel consumption, economic analysis, and environmental impact studies, but I am sure you can find those easily if you're interested.
- wpm 6y agoCHSR is like the worst case example of cost. That project is a disaster.
- nickff 6y agoI agree, but I see no reason to assume other states would be better. New York's subway cost spiral has been quite bad as well.
- Alupis 6y agoEvery contractor and their mother had their hand in the cookie jar. And every politician wanted a stop in their constituency town(s). This will not be any different nationally. It might actually be quite worse.
- ozzy6009 6y agoBased on this equation, shouldn't high speed trains consume less energy since they travel so much slower than planes (3x speed = 9x drag)?
- djsavvy 6y agoReally not sure whether the person you’re replying to is actually correct, but the air is a lot denser on the ground than at cruising altitude. That’ll have an effect on energy consumption that works in the other direction.
- iso947 6y agoOf course it’s not correct. A high speed train will use about 40kwh per 1000 people per mile A plane is about 5 tons an hour, or 10kg per 300 people per mile, so 30kg of jet fuel per 1000 people per mile, or 1.2GJ So a cruising a330 uses about 10 times the energy per passenger mile as an ICE high speed train. Clearly the comparison of polution caused it then affected by how green the electricity source is and the extra environmental impact of burning fuel in the high atmosphere.
- titzer 6y ago> high-speed trains consume more energy than aircraft citation needed. It helps a lot that (electric) trains do not need to carry their own fuel. Also, trains can run on low-carbon energy, whereas there is no viable alternative to jet fuel at the moment, and producing that from net-zero-carbon processes (akin to biodiesel) is not economical.
- nickff 6y agoAirliners travel in air that is >60% less dense than the air at sea level, and usually travel over or around energy-wasting terrain features and weather.
- titzer 6y agoThat's not a citation, it's a random factoid, which doesn't make for a fruitful discussion. Other random factoids include: * trains are long * trains travel slower than airplanes, and drag is proportional to the square of speed * making conclusions solely based drag coefficients from the density of the air is sound reasoning One of these statements is false. I get that hackernews is just a forum for casual discussion of various technical topics, but overly categorical statements based on a reasoning in a vacuum (no pun in intended) just force the conversation into unproductive threads like this one. I'm kinda sorry I took the bait at this point.
- deepnotderp 6y agoTrains are long, but skin friction drag is real. Traveling slower is a bug, not a feature. If you want to go slower, airplanes can be more efficient as well!
- kerkeslager 6y ago> I get that hackernews is just a forum for casual discussion of various technical topics I hear this sentiment a lot, and I don't understand it. Trying to speak the truth isn't just optional outside formal contexts. There's no situation so casual that I it suddenly becomes appropriate to make up bullshit and present it as facts. That is to say, I agree with your larger point: if nickff wants to make the claim that trains consume more energy than aircraft, he'd better come up with a reasonable source for that information.
- CydeWeys 6y agoThe advantage with the train though is that it can use renewably produced electricity, whereas the plane burns hydrocarbons.
- missedthecue 6y agoIt's pretty cheap to offset. About $5 to offset all the carbon produced during a transatlantic flight in economy seating
- charwalker 6y agoThat's great, but the environment doesn't care about the cost to offset just that it has less CO2/etc in the air from humans.
- CydeWeys 6y agoYeah, and the offset is directly causing that much less of the gas to be emitted into the atmosphere by someone else. CO2 is fungible. Rather than eliminating it from the hardest to eliminate use cases first (planes), it makes sense to tackle the easiest use cases first (power generation, trains, and road vehicles). Your dollar goes a lot farther there.
- missedthecue 6y agoCool. Air travel is not getting banned.