On: Crossing the USA by Train

[Symbiote]

London built several new stations in the centre of the city within the last few years, for the new Elizabeth Line.

London Bridge, a major station, was rebuilt.

Euston Station has a planned large expansion.

It's impossible to build an airport in a city centre.

[ghaff → Symbiote]

Not in a city center perhaps but Boston Logan is pretty close and London City isn't bad either.