sci.energy

Note this mainly underground project is costing $32b but will
bring $40b of benefits as well as 30,000 jobs. That is why
infrastructure spending creates wealth.
If a poor country like Brtain can build over 100 miles of
underground tunnels then why cant a superpower like USA build
thousands of miles?

Crossrail will add £20bn to the UK gross domestic product. Today's
go-ahead proves that London works best when London works together."
The tunnelled section of the line will be about 16 km (10 miles) in
length: a difficult and expensive piece of engineering, because of two
factors: London’s geology, and the extensive tunnelling that already
exists in central London. Its twin circular tunnels will have an
internal diameter of 6 m ( ft), compared with the m ( ft)
diameter of existing deep Tube lines. Rather than the third rail
electrification used by the London Underground or the existing North
Kent line, Crossrail will use 25 kV, 50 Hz AC Overhead Line in the
open air and a conductor bar contact system in the tunnels, the same
system as is present on the Great Eastern Main Line and the Great
Western Main Line (only as far as Heathrow