The plan
In my submission for an
HS2 spur for Liverpool and what could also act as the part of the
Liverpool to Manchester start of HS3, I have always intended that one
of the options would be to convert the line to GC standard and allow full High-Speed trains to run through to a new station under Lime Street via
the Victoria Tunnel. The cheaper option is to use classic compatibles on the route and terminate in the existing Lime Street, while this would both bring the journey time down by a considerable about, as the
trains could run unimpeded and at high speed for longer and free up capacity on the WCML for freight for the Port of Liverpool. It does not take
advantage of the longer trains for that additional work is needed and
new longer platforms.
The point at which the line east of Warrington crosses the proposed HS2 route is approximately 1 mile north of the junction from HS2 to the Manchester spur. It would be possible to provide an additional link between the Liverpool and Manchester Spurs rather than taking up space on HS2.
HS3 Junction |
HS2 to Ditton
The run from HS2 to Ditton
is not electrified and if it was expanded to GC Gauge and electrified
this would have no effect on the existing use of the line. However, there are several bridges, the height under which may need to be increased to allow for electrification and GC gauge. This can be done in two ways raising the bridge or lowering the track or by a combination of both. As the track can be worked from either end this should not present a major disruption to services.
It would be useful if the tracks
could still be used by standard WCML trains to accomplish this the
OHLE would have to be at a height that could be used by both.
The minimum separation
between OHLE and the body of the vehicle is 0.15m if we add this to
the 4.65m height of a GC Gauge vehicle we get a minimum height of
4.8m. Current electrical regulations require that at a level crossing
there is a 5.6 m clearance, as there are level crossing on WCML this
means that there is at least an 80cm overlap between acceptable OHLE heights
for GC and WCML. So a section of track within that window would be
usable by both.
The minimum clearance from
OHLE to static infrastructure is 20cm giving a minimum bridge height
of 5m above the rail top.
Ditton to Victoria Tunnel
However, beyond that, we are on the 4 line approach to Lime Street. In order to
fit GC Gauge trains on these lines. We would need to increase the available height and would have to use the same methods, as outlined earlier, though this would be complicated by the need to continue using the tracks, however, clearance has been increased on other lines without shutting the track there is no reason to believe it cannot be done here.
The additional requirement to allow GC
passage would be alterations to the platforms to allow GC trains to pass, this need only be done to platforms on the express lines, any none GC gauge train that needed to use these platforms would need
to have some mechanism for bridging the gap, the mechanism to do this
are an essential part of the Classic Compatible train design. Victoria Tunnel
Victoria tunnel |
The Victoria tunnel
would be used to provide access to a new station under the current
Lime Street, however, at 7.9 m wide and 5.5 m in height, the tunnel is not large enough to take 2 GC gauge lines. It is not
known whether that height includes or excludes the current ballast
depth.
The simplest way to
do this would be to lower the floor, while considerable
engineering work needs to be done, this is considerably easier and
faster to do than digging a new tunnel.
Calculations show
that the top of the rail height needs to be at least 1.62m below the
current tunnel floor. With the use of Ballast free track another
50cm, may be needed, making the total of increased depth 2.12m. At HS2 maximum incline of 1:40, this would mean an incline of great than 84.8 meters in length, to drop from current line-height to tunnel height.
Floor
lowering is by no means uncommon and such work has been suggested for
the Victoria Tunnel, in Queensland, Australia.
More information on the HS2 to Warrington section here at East of Lymm
More information on the HS2 to Warrington section here at East of Lymm
References
http://www.rgsonline.co.uk/Railway_Group_Standards/Energy/Railway
Group Standards/GERT8025 Iss 1.pdf
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