Does this sound natural for English speakers? "It is a commuter hell during Tokyo’s morning rush hour."

"i go to work by subway" is corrct because the preposition 'by' means via or in means of using something. the preposition 'on' means you are in the bus already and wouldn't make sense to tell someone that you are in the subway at work. "they go to school by bus." is corrcet because again the subject pronoun, they, needs to get to school not 'on' a bus but 'by' means of using a bus. the preposition 'on' in this case means that the the subject pronoun 'they' are already inside the bus.

By bus is correct and means using the bus as vehicle of transport . On bus is not proper to use ! same with subway , by subway but not on subway.

Yo uso "They go to school by bus." Es mas facil.