In message , at 12:15:25 on Mon,
5 Jun 2006, John Rowland
remarked:
Wembley Park, Finchley Road). So, although the two run
parallel for a while, I wouldn't say that they shared, as such.

They share a route, but as you say they don't share actual
tracks. A bit line the Piccadilly/District in west London.

I believe the technical term is they share a "formation".

Thanks
--
Roland Perry