In message , Richard J.
writes
Yes, Northfields and South Ealing are the stations,
on the Piccadilly Line. They are only 0.48km apart.

Is that the distance between the station buildings? The platforms
run towards each other, so the nearest ends of the platforms must
be only about 240 metres apart.

It's the distance quoted in CULG, and is probably an official LUL
distance, but I can find nothing on the site which indicates where such
distances are measured from.

The middle of the platforms is the only thing that would make sense.

If the far ends are 600m apart (underneath the roads they cross), and
the near ends are 250m apart; then that would be 425m, which is close
enough (given errors in the other two estimates).
--
Roland Perry