Why are trains no longer streamlined ?

[dcb]

Originally Posted by Bicycle Bob

...We still don't know how many year's worth of oil it will take to keep the dead reactors and their waste away from the biosphere, but that's another expense the next generation won't be able to afford...

That is my biggest concern, and I believe it is a valid concern, and I've not heard a real creditable response to it yet (We will enjoy the energy, you kids get to clean up the crud). Some folks get a little excited about it but I can only guess that it is because they have put a whole bunch of money in nuclear stock. I can't think of any other reason

[jamesqf]

After you finish checking the arithmetic on the 9 year energy payback fallacy, you could try looking into this one. The basic problem is the popular myth - created by comic books and '50s monster movies, and adopted by the watermelons* for their own purposes - that radioactive material is some sort of infinitely deadly stuff, like kryptonite. This bears about as much relationship to reality as does Superman or Godzilla.

*Watermelons: green on the outside, red on the inside.

[Clev]

Originally Posted by jamesqf

After you finish checking the arithmetic on the 9 year energy payback fallacy, you could try looking into this one. The basic problem is the popular myth - created by comic books and '50s monster movies, and adopted by the watermelons* for their own purposes - that radioactive material is some sort of infinitely deadly stuff, like kryptonite. This bears about as much relationship to reality as does Superman or Godzilla.

*Watermelons: green on the outside, red on the inside.

Nuclear waste is nasty, dangerous stuff. Until we can get the political will to implement breeder reactors to reprocess, reuse and reduce the existing waste, we shouldn't be building any more conventional nuke plants.

[Big Dave]

The US Navy has decommissioned scores of nuclear propulsion plants without incident. You let them sit for about six years and any residual beta or gamma emitters decay. Then you cut ‘em up like anything else. The US has decommissioned a handful of utility nukes and likewise had no problem.

As for the spent fuel rods, dealing with them begins with reprocessing them. About half of mass of all the “nuclear waste” in the US is usable U-235 in spent fuel rods. You reprocess it and recycle the fissile material back into the system. We know reprocessing technology works. The US was reprocessing fuel rods in the late 1940s.

The non-fissile portion has to go back to where every milligram of it came from – the earth’s crust. You let the beta and gamma emitters (always fairly short half-lifes) decay down to either an inert or alpha-emitting isotope and then you mix it with sand (about 250 parts sand to 1 part waste) and vitrify it. Drill a bore hole into a subduction zone and let plate tectonics bury it in the mantle. Howard Ballard – the guy who found the Titanic - suggested simply crushing the glass (it has about the same concentration of radioactive isotopes as uranium ore and is not soluble in water and is chemically as inert as things get) grind the cullet to fine granules and simply spread them widely into deep parts of the ocean. The abyss is covered by thick layers of mud and the heavy cullet will sink through it and be covered. The Marianas or Tonga Trenches would do nicely. Trenches are doubly good because they are formed by subduction, so the stuff is into the mantle within a couple hundred years. The French use vitrification and land burial and have had no trouble at all.

If you use fast-breeder technology, your “waste” contains about 108% of the fissile material that your “fuel” had in the first place. Drawback of fast breeders is that you have to “refuel” quite often to maximize the yield of fissile material. A regular reactor gets refueled about once a year. A fast breeder needs to be “refueled” every six weeks. This process converts non-fissile U-238 into fissile Pu-239. Fast breeders can also make the thorium cycle go. The fast breeder converts non-fissile Th-232 into fissile U-233. Thorium is far more ubiquitous in the earth’s crust than uranium.

Maybe because in my business I meet a lot of people who have worked around nuclear power, I have a lot of confidence in it. Nuclear power is proven and reliable and available as fast as you can license and build the plants.

If you simply cannot stand nuclear power, coal works just as well for generation of electric power.

Jamesqf’s estimate of 18 GW(e) sounds about right for electrification of railroads.

The cost of electrifying the railroads is high not because the catenary is so expensive but because you’d have to build an entirely new electrical T&D system to feed it. This, of course, ignores the cost of an additional 18 GW(e) of generation capacity.

Most railroad electrification puts one leg of the current in the track and the other leg(s) in overhead catenaries. This is much safer than “third rail” electrification.

Slug locomotives are used in both hump yards and as boosters for helper locomotives.

You know electrification is also possible for trucks on the Interstates.

[dcb]

Well, this thread is thoroughly hijacked. But of the options for nuclear waste disposal I like the subduction zone idea the best (assuming you have used the waste efficiently too). It seems like a lot less risk and cost than trying to bury it manually or blast it off the planet, and has a finality to it that does not imply any major maintenance tasks for some future generation to inherit, maybe keep an eye on the groundwater, might be worth some technology to ensure the waste gets buried deep and be able to track it, but I don't think you have to "guard" it at the bottom of a trench.

Course someone could devise a mud stirrir-upper, or the ocean currents could change and by some freak scenario move the mud, which could be a far fetched mess. It would also be nice to know there is nothing of "value" in the subduction zones, would want take a closer look before committing it to dump land.

It is kind of like "sweeping it under the rug" on a real grand scale

[spoil9]

Originally Posted by return2pa

Actually the prime mover (the diesel engine) in a modern locomotive is massive, not just large. Also, the main generator is much smaller compared to the prime mover, not larger.

You seem to be implying that some axles are un-powered. ANY modern locomotive has all axles powered (i.e. one traction motor for each axle). 6 axles = 6 motors.

I stand corrected.

[jamesqf]

Originally Posted by Clev

Nuclear waste is nasty, dangerous stuff.

Dangerous, yes, but nowhere near the "omigawd it's radioactive, we're all gona DIE!" level that people who apparently get their ideas from comic books and monster movies think it is.

And nowhere near as dangerous (per MWatt generated) as the waste from burning coal: the solid stuff causes cancer & respiratory diseases, buries houses (see recent news on the TVA spill) & pollutes rivers; the sulfur & nitrogen oxides cause acid rain; the CO2 may end up destroying human civilization... And there's a hell of a lot more of it to deal with - millions of tons every year, versus maybe a few hundred.

[jamesqf]

Originally Posted by Big Dave

The cost of electrifying the railroads is high not because the catenary is so expensive but because you’d have to build an entirely new electrical T&D system to feed it.

I don't see why. I'd think you'd want it as part of the grid, if only to provide more "inertia" in both systems. And since the grid needs to be upgraded to handle e.g. all that future distributed & intermittent generation, the railroad lines could be part of it. Use the RR right of way for transmission lines, put stepdown transformers where needed...

You know electrification is also possible for trucks on the Interstates.

And buses in cities, as in many European cities.

Though what I think would be an improvement would be electric buses with high-speed flywheels. That way you'd only need short stretches of overhead power lines at selected stops: the bus pulls up, stores energy from the overhead while the passengers are boarding, then uses line power for initial acceleration, and cruises to the next stop on the energy stored in the flywheel.

[Clev]

Originally Posted by jamesqf

Dangerous, yes, but nowhere near the "omigawd it's radioactive, we're all gona DIE!" level that people who apparently get their ideas from comic books and monster movies think it is.

And nowhere near as dangerous (per MWatt generated) as the waste from burning coal: the solid stuff causes cancer & respiratory diseases, buries houses (see recent news on the TVA spill) & pollutes rivers; the sulfur & nitrogen oxides cause acid rain; the CO2 may end up destroying human civilization... And there's a hell of a lot more of it to deal with - millions of tons every year, versus maybe a few hundred.

My point is, we have the technology to reprocess and reduce the waste, while generating even more electricity, but there's no political will. We need to get that changed first.

[MetroMPG]

Today's nuclear power debate is brought to you by... trains!

Originally Posted by aerohead

Hoerner has a section on trains in his book,"Aerodynamic Drag." I'll dig it out and post that,but I think Bicycle Bob and Big Dave have covered the fundamentals of it.

I happened across a paragraph in Hucho, with an interesting tidbit about rear taper.

He repeats that due to their length, the boundary layer is very thick by the end of the body. So much so that:

...at the end of a train ... (it) is hardly able to overcome any adverse pressure gradient at all. Therefore, in contrast to a road vehicle, the shape of the rear has minor influence on the drag of a train. Furthermore, with modern high-speed trains like the ICE or TGV, the shape of the rear end is not selected on the basis of the flow field generated at the rear. This is because these trains go back and forth without turning around, and so the contour of the locomotives is the same at both ends, and is determined by the requirements of a front end.

Interesting. Learned something new today.

We now return you to your nuclear debate...