I just looked at the timetable for the Cheshunt/Chingford lines,

http://www.tfl.gov.uk/cdn/static/cms...e-may-2015.pdf

and during the repeating sections (all day Saturday and Sunday and bits
on weekdays), there are 8 tph between Liverpool Street and Hackney
Downs, with alternating 1 minute and 14 minute gaps in either direction
at Hackney Downs!

The line map is also crap... it uses a dagger to show that trains to and
from Chingford do not call at London Fields or Cambridge Heath, instead
of just drawing separate lines interchanging at Hackney Downs, like this
http://www.londonbusblinds.com/prodi...tan%20Line.jpg