Instead of a shinkasen running every six minutes, we get a low-speed train that runs about once an hour, and only during working hours. If you work past 8 PM you're going to have to find another way home.
I don't really know what's far enough, but culturally they consider themselves entirely distinct. People from one almost never work in the other; the trains that do exist are for bringing people from the suburbs.
Even those suburbs are fairly distinct. There's a dividing line at Columbia, MD where people go both directions, and nearly everybody else affiliates themselves with one city or the other.
Another way to look at it: they have separate sports teams. They're not even rivals, because they play in different leagues. Within the city fans are pretty exclusive, and the other city's teams aren't of interest.
Maybe that would change if it were possible to live in one and work in the other, or if they commonly shared night-life or restaurants or leisure. Instead, the other city is a full-day trip, not a jaunt across town.
None of what’s in this comment or others reflects my experience at all. I work in DC and have had many colleagues who live in downtown Baltimore and Baltimore suburbs, even suburbs north of Baltimore. They have been Orioles fans. Some have driven, others take commuter rail. I live in a suburb that is closer to DC but the commuter pattern on the highway reflects traffic flow to the Baltimore area in the morning and away from it in the evening. My wife and I work in downtown DC and we live closer to DC than Baltimore, but we routinely attend cultural and recreational events in Baltimore and of course fly from the Baltimore airport. We had memberships in the National Aquarium (in Baltimore) and have taken our kids to the Maryland Zoo. They have never been to the National Zoo in DC.
Baltimore and DC are absolutely one metro, just like Dallas/Fort Worth and Minneapolis/Saint Paul. That two cities have distinct identities doesn’t mean they aren’t one metro.
I don't really know what's far enough, but culturally they consider themselves entirely distinct. People from one almost never work in the other; the trains that do exist are for bringing people from the suburbs.
Even those suburbs are fairly distinct. There's a dividing line at Columbia, MD where people go both directions, and nearly everybody else affiliates themselves with one city or the other.
Another way to look at it: they have separate sports teams. They're not even rivals, because they play in different leagues. Within the city fans are pretty exclusive, and the other city's teams aren't of interest.
Maybe that would change if it were possible to live in one and work in the other, or if they commonly shared night-life or restaurants or leisure. Instead, the other city is a full-day trip, not a jaunt across town.