In message , at 11:58:31 on Wed, 20 Jul
2011, Clive Page remarked:
SLL extension new works by Birse Metro. The contractor's site he

http://www.overgroundextension.co.uk

Is it reasonable to call it a "frequent" service if there are only 4
trains/hour?

Many people would kill for 4tph. My own view (coloured in some part by
being a past user of the outer fringes of the Met line) is that
something magic happens between 3tph and 4tph - despite it only reducing
the interval by 5 minutes. Such that 4tph is a frequent enough service
it's turn-up-and-go for most users.
--
Roland Perry