Ulrich The Wikipedia article states that the new tunnel (is really two tunnels) will have two single track side by side bores, with passageways connecting the two tunnels allowing trains to move from one tunnel to the other every thousand feet or so. Why two tunnels instead of one large double track bore?
The Wikipedia article states that the new tunnel (is really two tunnels) will have two single track side by side bores, with passageways connecting the two tunnels allowing trains to move from one tunnel to the other every thousand feet or so. Why two tunnels instead of one large double track bore?
Isn't the double bore configuration for extremely long modern rail tunnels pretty standard now? I know the Channel tunnel was built that way.
I can think of several advantages...if the tunnels are being built with Tunnel Boring Machines than smaller diameter (and thus cheaper to buy and operate) machines can be utilized. there are also the safety and redundancy advantages mentioned by another poster. And correct me if I'm mistaken but wouldn't a larger diameter double track tunnel actually require the removal of more rock to contruct compared to two single track tunnels (given a circular tunnel bore)?
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
Just a suggestion: a derailment or other calamity is less likely to shut the entire system down if the tracks are kept separate. It may also be less expensive to drill this way.
Carl
Railroader Emeritus (practiced railroading for 46 years--and in 2010 I finally got it right!)
CAACSCOCOM--I don't want to behave improperly, so I just won't behave at all. (SM)
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