Yes, you CAN power full-scale trains with solar + a battery. This train has solar panels on its roof + solar panels on a storage building next to where it parks. These solar panels collectively generate electricity, which then fills the train's battery and powers the train.
One of the great myths about electric cars is that "they" are too expensive -- and usually when someone uses "they" to refer to electric cars they mean ALL electric cars are allegedly "too expensive".
Nissan used to lead electric car sales in the United States regularly with its first generation LEAF, which became available in the U.S. in 2011. But, at least anecdotally, it does not seem to be doing nearly as well with its second generation LEAF in the U.S., of which I have seen exactly three in a full year of looking here in the Denver, Colo. area.
There is still a lot of misinformation and anti-electric car stuff being pumped out onto the internet by folks who, for the most part, have a vested interest in the continuation of #BigOil's economic -- and environmental -- hegemony. One of the biggest myths about electric cars is that they are "too expensive". Not true. Simply. Not. True. Case in point: My own experience owning, and driving, an electric car for the past five years.