3 ms·
I encourage anybody who gets the opportunity to ride the green line. It's cool that they managed to build it in a time before tunnel boring machines (by literal
by bloppe 11mo ago
I encourage anybody who gets the opportunity to ride the green line. It's cool that they managed to build it in a time before tunnel boring machines (by literally digging a huge, long pit, building the track, then covering it with a roof and dirt again). Just wear noise cancelling headphones or something cuz those trains screech
- laurencerowe 11mo agoCut and cover is still the cheapest way to build subways, but is less often used nowadays because of the surface disruption. Long before tunnel boring machines existed we needed to develop methods to dig under rivers. Brunel invented the tunnelling shield for digging under the Thames in 1825 and later a more refined version was used to dig the first deep-level tube line which opened in 1890. https://en.wikipedia.org/wiki/Tunnelling_shield https://en.wikipedia.org/wiki/Tunnelling_shield
- IAmBroom 11mo agoTHIS kind of comment is what makes HN gold! TIL...