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Comment by Merrill | Hacker News Reader

This is valid for rail travel in Europe if the energy for electrified intercity rail is not sourced from hydrocarbons. The energy efficiency in MegaJoules per passenger-kilometer are about equal between rail and air. For freight, rail is much more efficient in MegaJoules per ton-kilometer, but passengers are a small percentage of a very heavy rail car.

In the US, other than the Boston-Washington corridor, intercity rail is diesel powered and travels at 90 mph max due to grade crossings of roads and streets and due to track curvature. To fix US intercity rail requires removing all grade crossings, realigning the railways to straighten curves and redesigning the roadbeds to support high speed operation.

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> The energy efficiency in MegaJoules per passenger-kilometer are about equal between rail and air.

Do you have a source for that ? I'm interested.

Your energy calculations seem implausible, irrelevant, and perhaps even sinister sinister. (similar to the conservative talking point about how busses, per passenger, are less efficient than cares because busses don't operate on average at capacity).

Do you have any articles or studies where you can see the CO2 output pr passengers with train on diesel vs electric (sourced from various hydrocarbons) vs air travel?

It would be interesting to see actual numbers and you seem to have studied this a bit.

If you make a trip simulation in France you'll get the numbers from SNCF. E.g. try Trainline.eu. I couldn't find where they come from though.

See page 14, 15 of "Energy Efficiency in Air Transportation" by Arturo Benito, Gustavo Alonso. Table 2.3 gives MJ/pkm for the US. Fig 2.8 next page gives ranges of efficiency for both passenger and freight.

https://books.google.com/books?id=jJGZDgAAQBAJ&printsec=fron...

Back when "peak oil" was a thing, I was in several discussions about what it would take to electrify the US transportation networks, both passenger and freight, but I have not worked in transportation planning. Hydrogen-fueled intercity buses will be much easier to implement than anything else, especially if they are autonomous to reduce driver costs.

Thanks for the source.

It only lists raw energy use and not greenhouse gas emissions though. I'm a bit surprised since the tables I've seen have train emission at the very bottom, but most of what I have seen is from Europe but we run diesel trains here in Norway too (in the north) and the tracks are not straight at all!

https://www.eea.europa.eu/data-and-maps/daviz/specific-co2-e...

Rail: 28 g/passenger km Air: 244 g/passenger km (road 101 g/passenger km)

2014 figures. Edit: Units !!

The numbers are in g/passenger-km, not kg/passenger-km, thank God.

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