3 ms·
most of the original tunneling was done by hand, so i'm not sure if it's directly comparable. There was an interesting article regarding the heat transfer to th
by robbiep 7y ago
most of the original tunneling was done by hand, so i'm not sure if it's directly comparable. There was an interesting article regarding the heat transfer to the surrounding ground recently - [0] that i'm sure you'll find interesting if you haven't seen it before!
- bobthepanda 7y agoJubilee Line Extension was the '90s and Crossrail is opening soon, so those definitely weren't by hand! I have seen articles about it, as well as a recent proposal to use that heat for heating homes. But it just illustrates the (many) potential pitfalls of small diameter tunnels, because you really don't want your tunnel to become an oven after a few decades of heat generated from braking. Other pitfalls include: You need space for adequate ventilation. This is less of a problem with electric propulsion, but you do still need it for emergencies (like a fire). And then there's the issue of noise; if your vehicle is too small compared to the tunnel, then the air being forced out once you get to a larger space (like the outside or a station) creates loud noise. Japanese high speed rail trains have much stranger aerodynamic shapes than European ones because they built smaller diameter tunnels and this ended up causing noise issues at higher speeds.