Later on the journey our train used a new rail crossover viaduct. On the way up to King's Cross I'd noticed the new embankment twisting away to the right.
Braunston
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Well it was fine when we left home at 10 am but that was to soon change and
at times the road spray made driving pretty grim, however by the time we
reac...
6 hours ago
5 comments:
The tubular bridge carries the High Speed lines from Kent and Eutotunnel on their way into St Pancras. They rise from underground and cross the bridge inside the tube. No idea why that is necessary though.
Mike
Nb Duxllandyn
this is the bridge I guess https://www.google.be/maps/@51.5410992,-0.1227463,208m/data=!3m1!1e3
I agree it is a strange contraption. The only reason I see is that the line to the east goes into a tunnel and the engineers could not (in the restricted space) make a proper tunnel entrance after the bridge, so they use the bridge for that purpose, eliminating risk of rain etc to enter the tunnel.
And also this might be part of the special security measures for HS1, to avoid that dangerous continentals like me enter the country without proper security checks.
Thanks Mike and Frank. Now, why didn't I think of looking at Google Maps?
The reason for the "tunnel" is that without it the train would exit one real tunnel into a very short section of daylight then another real tunnel.
We all know what happens entering a canal tunnel when your eyes take time to adjust to the dark and you can't see anything for a few seconds.
The continuous "tunnel" ensures train drivers can continuously observe where they are going and see signals and their cab displays properly.
Wow! Thanks Paul. I hadn't thought of that.
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