Solar ?
Would never come close to electrical grnerators.
Standard rail car wheel = 36" inches 1 mile per hour = 9.34 rpm's ( revolutions per minute )
40 miles per hour = 373.6 rpm https://www.omnicalculator.com/everyday-life/rpm What does a 1 MW electrical generator require for revolutions ?
If one is familar with gears / ratios
One would need a worm gear amplifer of, 10:1
40 miles per hour
= 373.6 rpm
x 10 gear amplifer
= 3, 736 rpms
One has just achieved a secondary purposing of, locomotive wheels.
Delivery of goods + grnerating power
Power not attached to grid with expensive rates
rather - power produced by rail owner partnered with miner.
Number of box cars fitted with generators + battery banks
dictates amount of usable stored electricty.
1MW GENERATOR
SPECS / PRICING
https://ae01.alicdn.com/kf/S53fc376a235b4c3892db86734b1651fbZ.jpg?width=1164&height=755&hash=1919
Again, solar could never compare to electrical generators.
What i've just outlined is perhaps an entirely... NEW REVOLUTIONARY IDEA.
Practable / Doable.
Smart ideas that resolve.