[ale] [OT][Way OT] Industrial Power Question

[Thompson Freeman]

My apologies to those who really don't want to see this.  
Unfortunately ALE is one place where I can consistently  
find intelligent technically informed people, so on the  
chance ...

During the era of $4/gallon fuel, I got to blue sky  
thinking about solar power and transportation.  
Specifically, rail and/or light rail.

If my back-of-the-envelop calculations are anywhere near  
correct, it is now technically feasible to run a rail  
transportation system (say like MARTA for instance)  
entirely from solar power collected from the right of way  
of the tracks and the roofs of the stations.

I have recently seen a short article claiming a thermal  
solar conversion system is economically competitive with  
more traditional electric generation schemes.

For the back of the envelope stuff...

My understanding is that current solar collection runs  
about 1 watt/sq ft of collection area. To allow for clouds  
etc, take that to 0.5 watt/sq ft. Lets use a figure of 1  
horsepower=1kw, which is some 20% high, but keeps the  
number simple and turns on a light also. The Charlotte Lynx  
system runs vehicles of 780 rated horsepower, which means  
that MARTA may be up to a thousand?? In any event, 780x2000  
suggests Charlotte would need to dedicate 1.5 million sq ft  
of collection per running vehicle for full power usage.  
Since the vehicles are under full power for only short  
periods of time that 1.5 million figure is probably a  
multiple of the required power needs, but I don't have the  
background to make the adjustment. In any event, that  
figure is approximately a strip 14 miles long by 20 ft  
wide, or the right of way available to one track of the  
Lynx line here.

The question I have for the bright people here is "Can you  
refine these figures/guesses to something a little more  
defensible?"

I probably should offer to purchase a round of virtual beer  
for the participants...

Thanks for the use of bandwidth, and the opportunity to  
scratch a nagging itch.