Ascendant Trolley

from Slate

Why is the trolley ascendant as the monorail declines?

This article compares the relative merits of trolleys and monorails. The key difference between these two modes of transport is that the monorail whizzes past you in the sky while the trolley rumbles alongside you, earthbound and familiar.

But when Tom Vanderbilt notes that the ground-based system is winning more approval than the sky-based one, he refers to the trolley as "ascendant." This spatial metaphor could mean that rather than gaining more popularity, there has instead been a trend of trolleys blasting off into the heavens, like Chitty Chitty Bang Bang. Streetcars also ascend, on page 2.

But what is a flying trolley, if not a monorail? And isn't a declining monorail a subway?