In message om, sweek
writes

You guys are confusing the Tube map (LU + DLR + North London Line)
with the Connections map, showing all passenger raill ines in London.
TfL has also released a 2010 Tube Map earlier this year, clearly
showing that the whole Overground would appear on the map in orange.
http://www.bbc.co.uk/london/pdf/tube_map2010.pdf

Ah, I see that the idea of moving Hainault loop stations into Zone 4
will have failed by then.

--
Paul Terry