I do like trains, and if they were more efficient and cost-effective, I would choose to do a lot of short-haul travel on them.  But I have one major objection to the build-up of long distance train infrastructure: biodiversity corridors.

Our open space disappears so quickly; I believe that if we do not work very hard to protect a few large corridors of land, large predators like the grizzly will disappear. Since large predators are at the top of the food chain, their disappearance necessarily causes ripple effects on the entire eco-system.

I would much prefer to support efforts at new technology (there's that word again) that would address air travel's environmental problems, than to lay down train tracks across the nation, and cut down even more trees to do so.

I doubt you will ever have train tracks do anything like the damage highways do. And in most cases it would make sense to run them in parallel to existing highways.

In the long run trains can substitute for a lot of our roads and highways - so this is a gain, not a loss for biodiversity.

In terms of improving planes - at level we would need, does not look likely in the short or medium one. Most people think it will take us twenty years to develop a plane as fast as our current jets with a low climate impact.

They are working on that fuel cell/turbine backup generator Gar.  How hard would it be to scale it up to a turbofan engine?

If a huge new defense contract were issued?  Get on this Washington state legislators.  Democrats can inherit the wind of legendary defense pork barrel democrat Scoop Jackson and do something green that still brings in the big contractor "donations" (bribes).

With three times the mileage or more, air force planes could carry even more napalm!!  Excellent.

The army funded a hybrid hummer, the navy even has a wave power station in Hawaii.

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Gar, this is excellent advice.

Just so that we all understand: flight between, say, Toronto and Vancouver involves costly transportation from somewhere livable in or around Toronto to the Toronto airport, and also transportation from the Vancouver airport to somewhere livable in or around Vancouver.  And that extra transportation on either end costs something.

On the other hand, trains usually put us down within cities, within significantly small distances of our ultimate destinations.

Also, I entirely trust Gar, that the building of new roads to accommodate vehicles must surely be a bigger threat to such animals as grizzlies than a renewed interest in railroads, which in North America are already mostly in place.

(Lamy, New Mexico, is perhaps a bit anomalous in this regard.  It is the train stop for Santa Fe, several miles to the south of that glorious city.  Otherwise, Lamy itself is barely anything.  But the tracks between Topeka and Albuquerque have stayed in the lowlands, and climbing up to Santa Fe, higher than Denver, was apparently almost always too much of a challenge.  When last I traveled that way, there was a shuttle bus, with a very nice driver, who took $20 and more for the favor of your being driven between Lamy and any of a few large hotels in Santa Fe, and vice versa.)

We ought to be able to replace much airplane travel with trains.  We also ought to be able to replace much interstate truck travel with trains.  There will apparently be a need for local-service trucks and buses, between  train stations and bus stations, and center-city locations, for a long time to come.  Surely that is preferable to the absurd status-quo, a drive of at least a half hour from some lifeless exurban wasteland called an airfield.

Chickens are our cousins! So are other sensitive animals! Enough is enough! No more factory farms!

>They are working on that fuel cell/turbine backup generator Gar.  How hard would it be to scale it up to a turbofan engine?

Pretty hard. A jet engine's power comes in part from the compression, but also from ignition and expansion of hot gases. In other words burning something, and extreme heat is part of what drives an airplane jet engine. Making a jet engine that depends 100% on electricity to compress air is not just a matter of scaling: it is something fundamentally different from what we are doing now. It is not physically impossible: some of the tricks rocket scientists are working on might adapt to powering a true 100% electric jet. But no one has built a working model.  I don't think anyone has even created a computer model for a billion dollar prototype. (Sometimes you will hear the term "all-electric airplane" used to refer to an aircraft where all auxillary power comes from electricity. But the jet engine still runs on fuel.) We can and have built all-electric turbo props and all-electric helicopters - though ranges are limited.  But, as far as I know, nobody has built an all-electric, or all fuel cell based jet plane.

That is really interesting. Especially this:

>This yields a dry (no steam) hybrid-cycle power system that promotes unprecedented electrical generation efficiency.

Only - a jet engine does not use electricity for thrust. Electricity on air craft is for starting an engine, and for auxillary services. So I'd still be curious to see figures on water emissions and fuel use per amount of thrust. I suspect there is a reason this is being considered only for auxillary services and not to power the main engine. But I don't know that. I'd like to see the numbers.

Well I'm talking turbofan for that very reason Gar.  The fan provides most of the thrust.

It would need a very high power electric motor built into the turbofan rotor somewhere.  The newest brushless DC electric car motors without permanent magnets might be suitable, they are much lighter than their predecessors.

But I admit this is mainly sci-fi, as are a lot of my speculative concepts.

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E=MC2

Saving time requires energy squared.  Double speed cost four times the energy.  Four times the speed costs sixteen times the energy.  No escape from reality.

>Saving time requires energy squared.  Double speed cost four times the energy.  Four times the speed costs sixteen times the energy.  No escape from reality.

Which is where things like Maglev on the ground come it. Not more energy efficienct, but able to use wind and solar electricity - which makes them carbon efficient.

Canis, Lamy isn't an accident, or a feature of Santa Fe's elevation.  The railroad companies asked cities to pony up for the privilege of having major rail lines go through them, and Santa Fe didn't, but Albuquerque did, which is why the railroad goes the direction it does.  I think Santa Fe thought it was so important politically and culturally that it didn't need to pay to maintain that importance, and it quickly saw the error of its ways, but too late.  

There's a smaller spur line from Lamy to Santa Fe--originally it went up to Espanola, and I think even to Taos, but those tracks are all gone, as far as I know.  Supposedly the new commuter service will use/is using the existing track from Albuquerque to Lamy and then Lamy to Santa Fe, but I haven't been home enough lately to know how/if it's working.

As much as I dislike the idea of using hydrogen for cars, I do think there are a lot of advantages in using liquid hydrogen as jet fuel. It is light, it is clean, and its flame has a lower temperature, reducing the potentials of forming NOx.

Now, safety may still be a concern...

>s much as I dislike the idea of using hydrogen for cars, I do think there are a lot of advantages in using liquid hydrogen as jet fuel.

The problem here is that hydrogen may decrease CO2 and NOx, but it increases water vapor. Near the ground water vapor is a feedback, but at that height water vapor is a forcing. And water vapor as a forcing is more powerful than CO2, even more powerful than NO2 (though not as long lasting). In short, planes are the one place where hydrogen (even from wind or solar electricity) has no greenhouse benefits.

Easier to fly them high, both for safety and to reduce air friction.

I am skeptical.  Sounds more like resistance to new routines.  Noise was my concern but that sounds much easier to fix than the high altitude GHG water vapor of jets.  I do not like jet noise but hate global warming much much more.  Jet travel doubles the per capita GHG footprint (British data).   Fly at or below cloud level.

Low flying planes use more fuel - a lot more fuel. So if driven by fossil fuel you would be cutting emissions from around 3X auto emissions per mile to around 2X or around 1.5X. And plane travel especially over water (since we can use trains for land) covers a lot more miles than most land journeys. What about hydrogen? According to Monbiot, hydrogen, even though higher density the kerosene by weight is lower by volume (even liquid hydrogen). So you have to have larger heavier fuel tanks. And in turns out that hydrogen jets are too heavy to fly long at low altitudes. You have to fly them at high altitudes.

OK - so that leaves runnning low flying jets on biofuel. (Someone has developed a process for jet biofuel that makes a fuel comparable to kerosene.)  But running less efficient planes on biofuel is not going to leave much for anybody else if you continue to use planes as much as we do.

You can't do much of it, because there is a limit to how much biofuel we can produce sustainably. Although one of the arguments against biofuel is the high energy inputs use to produce it. But in this case the fuel is doing something that, say, solar heat or low carbon electricity can't. So if you have to use these as inputs to produce biofuel with a very small net energy gain, it might still be worthwhile. Substituting internet communication and trains wherever possible is the first step. But running those jets we need to fly (mainly the ones over water) at low altitudes on biofuel might be the last step.

Back in the 1960s I used to make model airplanes...which required model airplane glue.   Yes, I know what you're going to say, but I didn't sniff it other than the sidestream fumes.

Then around the 1970's they came out with "safe" model glues.  They were based around citrus bases of some sort and smelled like lemons and oranges.   They took the original model airplane glue off the market.

You know what?  That new glue was terrible!  It never dried and the pieces just kind of sagged with the rudder of my B-17 just falling limp to one side.

That always seems the way with "alternatives" or "safe substitute".   Engineers know: you don't get something for nothing.   You can't go around expecting to make everything all Green and still get the power and utility of traditional technology.

Everything has its cost.

Did Mankind not yet learn that?

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Another approach might be to use hydrogen as a lifting gas and then electric motors and pv panels to propel the craft.

>Another approach might be to use hydrogen as a lifting gas and then electric motors and pv panels to propel the craft.

Not going to be as fast as a jet.

Contrary to JB, in most cases green tech can be as fast, efficient convenient ect as brown tech. But air travel across water is an exception. While stuff like MagLev can get us across land as fast as airplanes (though probably at a higher price), travel across water will simply have to be done less or more slowly.