You’ve proven yourself wrong.
Mochi Tetsu is mentioned in that article as being a source that produces higher quality products than iron sand. Exactly what you’re arguing against.
The facts are that due to the limited availability of good quality iron ore the steel produced in Japan often used iron sand and that led to lower quality products.
Trains are easy and they’re easily electrified already. So putting solar on the trains won’t have any advantage.
Rails are the difficult part of railways. They never seem to put them between my house and my work. They’ve put something called a road in between instead.