"David Hansen" wrote in message

On Thu, 08 Oct 2009 15:16:26 +0100 someone who may be eastender
wrote this:-

I think if they'd had a bit more cash they could have at least added
a third line along the stretch from Dalston to wherever possible
southwards - after all that trackbed used to have four tracks - I
think?

The line was widened over the years, but IIRC four tracks ran all
the way northwards from Broad Street station to Dalston Junction.
IIRC they were called the No 1 and No 2 lines and it was the former
which were electrified. At Dalston Junction four lines turned west
and two lines turned west. The electrified lines were used by
services to places like Watford Junction and Richmond, the
non-electrified lines were used by services to places like Welwyn
Garden City and, in earlier times, services to the docks.

I believe that the two new stations on the old Broad St line take
advantage of the four-track formation. In other words, the new platforms
are built over the previous outer lines. So they wouldn't have been able
to fit in more than double track on the viaduct south of Dalston.