[Talk-GB] Railway: 'The Chiltern Line' North West London

[Dave F]

Hi
I've been tidying up London underground stations & Lines. I came across 
a section used as the Metropolitan Line but labelled as name=Chiltern 
Line. Coloured red:

http://overpass-turbo.eu/s/ELp

  I'm aware Chiltern Railways run services on that shared line, but is 
'Chiltern Line' an official designation? Would alt_name/Loc_name be more 
appropriate? Anybody local who can advise?

The 'Chiltern Main Line' is coloured blue & looks accurate.

Also, the stretch between Chorley Wood & Chalfont & Latimer is shown as 
a single track. Is there a reason other than the other line hasn't been 
mapped yet?

Cheers
DaveF