https://en.wikipedia.org/wiki/Massachusetts_Bay_Transportation_Authority#Subway
https://cdn.mbta.com/sites/default/files/maps/2019-04-08-rapid-transit-key-bus-routes-map-v33.pdf
https://cdn.mbta.com/sites/default/files/maps/2019-04-08-commuter-rail-map-v33.pdf
https://en.wikipedia.org/wiki/List_of_United_States_rapid_transit_systems_by_ridership
https://en.wikipedia.org/wiki/List_of_United_States_light_rail_systems_by_ridership