Why Japan has such good railways

I have lived in NYC my whole life and visiting Japan was culture shock in terms of how clean their subways are. THEY HAD BATHROOMS! Clean ones! No stench of urine or 125 years of moist caked filth. Vending machines on the platforms are a welcome touch. No water dripping from the ceiling or puddles on platforms that may or may not be pee or liquefied human remains, lord knows. No rats scurrying around.

Geography is destiny.

In part, Japan has good geography for passenger rail. Most of the population lives near sea level and therefore a lot can be done without significant grades, and because the island is long and skinny, even the highest point in the network is less than 5000' and there's just one mountain range to cross.

And of course population density.