From "Beyond HS2" by Greengate 21
The known and unsolved capacity constraints on both the Great Eastern Main
Line (precluding the sought-after speed-up of Norwich services through the day)
and on the West Anglia line (meaning slow journeys to/from Stansted Airport and
Cambridge) can be overcome, but not by the relatively modest level of adaptations
to the existing lines considered in studies to date. Instead, consideration needs to
be given to a new approach that would maximise the benefits of new high-speed
line construction. Like HS2, this would need to ‘plug into’ the existing rail network
and offer a bypass to its most critically over-stretched line segments. Unlike HS2
(under current plans) it could offer a direct interchange with HS1.
A high-speed line could be built, for example, along the M11 corridor from Stratford
initially in tunnel, and branching beyond Stansted Airport to link the Great Eastern
and West Anglia Main Lines. London terminus points could be at Stratford, or
Canary Wharf (from which a cross-London route southwards for high-speed trains
could be fashioned) or Liverpool Street (but the approach and station facilities here
would be expensive). Stratford has excellent onward connections (enhanced further
by the Elizabeth Line) and there is scope for ‘place-making’ around a new expanded
station as has been done at Kings Cross/St Pancras.
Such a link – illustrated in Figure 8.2 – would offer a rich set of benefits:
» A new faster route from Cambridge to London;
» Better access for Stansted Airport, with a fast (target: 15-minute) rail
link to London and much improved direct connectivity to the airport
from across East Anglia;
» Capacity relief to the Great Eastern Main Line, with a faster route via
Stansted Airport for London trains from Norfolk and Suffolk, and the
scope to intensify services from north Essex into the capital. A journey
time of 25 mins – nearly halving times from Colchester to a new
London terminus at Stratford would be feasible; ‘Norwich in 90’ would
be readily achievable through the day;
» Released capacity to allow service expansion along the Lea Valley and
support its associated development. This would support Crossrail 2 in
due course and enable its operation to be segregated from the longer
distance national rail network;
» A new cross-country axis between the North/Midlands-CambridgeStansted-Colchester-Ipswich;
» The capacity released in the Lea Valley could also potentially be used
for freight from Tilbury/Thames Gateway (although this would need
a new junction at Tottenham Hale), and/or there might be scope for
a strategic freight interchange and associated railfreight flows. This
might allow the southern end of the East Coast Main Line to be freed
of freight;
» If later extended north of Cambridge to Peterborough (either by line of
route upgrade or further new build), provide capacity relief to the East
Coast Main Line and potentially (after 2040) form the southern end of
a second north-south high-speed line;
» Act as a complement to the Felixstowe to Nuneaton freight route and
a plausible extension to East-West Rail
http://www.greengauge21.net/wp-content/uploads/Beyond_HS2WEB.pdf