Quote:
Originally Posted by PDUB
On the scale of the water wheel it works because the energy put in is more that the parasitic drag on the wheel... on your railroad, the drag would very quickly overcome any efficiency realized by the gravity fed cars coming down the hill loaded with coal... it is too far to the powerplant to make it work... thus the perpetual motion reference.
As for the electric power superhighway, once low-cost room temperature superconductors are found, this will become a reality  !
'Til then, you are stuck doin' what you're doin', so keep on truckin'  ... the stockholders are hungry  ! |
I know I'm stuck, unless I want to go back to hoisting drywall at my age. Not that the exercise wouldn't do me some good again.
While there certainly is railcar parasitic drag, it is not one of the things that would prevent significant energy from being extracted from coal cars rolling downhill. Don't worry, I have given this thought before imagineering.
To understand, imagine water flowing downhill of its own accord. We all know that energy can, and is, extracted from this gravity principle. (It may seem like perpetual motion, but energy from the sun causes rain and snow to accumulate near the Continental Divide and the gravity does the rest.) Many streams and rivers, such as the Missouri, flow quite slowly, 4-5 mph, but provide a considerable amount of power per 1000 cubic foot of flow.
From railroad experience, I can tell you that a coal train rolling down the same grade, will far outrun the water, because of lower drag. There are relatively level areas of track where I coast for 30-40 miles at 50 mph, sometimes forced to add a bit of dynamic brake to keep from speeding. The true downhills are much more demanding, causing me to need all the dynamic braking and half my airbrakes. The amount of regenerated power wasted out the top of the blower grids (think toaster elements) would run a small city, plus smoking all 900+ plus brake shoes. Of course, it only take about 10 minutes to get to the bottom of my little hills, as opposed to actual mountain grades west of me. There, rivers run white-water.
Here is an interesting rolling resistance table. Looking at the difference between rubber tires and steel wheels, it is easy to see why Warren Buffett is investing in future transportation in the rail end of it. Actually, I am a BNSF stock-holder myself, privately and in 401K. But I am invested in common stock as opposed to Warrens preferred stock. Never-the-less, I work myself too hard.
The idea that, "low-cost room temperature superconductors" will help power lines is true. Long transmission lines could pass power long distances with little loss if constructed thusly. But this is way out there. On the other hand, present super-cooled superconductors can improve local transformers, I would think.
Present super-cooled superconductors can also maintain and even improve low "rolling resistance" in
Maglev trains. I see the main advantage as extremely low track maintainence, one of the glaring flaws in my circle-train concept. Hard to work on worn track with a train moving on it.
There is technology already afoot to make transmission more viable. What I am speaking of is Siemens HV Direct Current Transmission System (
HVDC). With very high voltage, power losses are greatly minimised. With DC instead of AC, fluctuating magnetic and corona losses are further minimised. Siemens engineered the inverter technology in our newest locomotives that allows huge AC currents to be handled by solid state devices and eliminated troublesome brush type DC traction motors. I got to ride in prototypes. We've come a long way since our transistorised audio amplifiers tended to blow out. Siemans is from Germany. I don't know if HVDC is being fully adapted in the US, as we are getting a bit behind other progressive nations, to call a spade a spade.
I have a perpetual motion story in mind. A new thread is in order just as soon as I get time.
Wes
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