surface subway
n.— «One thing that Aaron should absolutely be ashamed of himself for is his use of the phrase “surface subway.” Subways and elevated trains speed people along because they’re grade-separated. You just can’t go that fast on the surface, even if you have a dedicated right-of-way and signal priority. A surface subway is nonsense.» —“I Want a Nice Big Imitation Steak” Cap’n Transit Rides Again Jan. 19, 2009. (source: Double-Tongued Dictionary)
Further reading
Imagine telling someone how to get to your home, but without using the name of your street, or any other street within ten miles. Could you do it? We take street names for granted, but these words are useful for far more, like applying for a job or...
People might never know that quality jazz exists outside the city of Baton Rouge. Which may be true—but it’s also a pangram. This is part of a complete episode.
Related
Here is something close. Part of Philadelphia transportation system is known as “subway surface.” These are trolley cars that run on the streets at the outer portion of the city and then descend into subway lines when they get near the center of the city.