Isn't the problem that the requirements for line were "gold plated"? If they'd put in another standard rail line instead, it would have increased capacity, taken up much less space, would have been much cheaper, would have caused less disruption and would have had a clearer business case.
Japan built the first Shinkansen while British Rail was still running steam services. Can't stay on the Victorian era rail constraints forever.
(it's very British to say "this is too good, can we have something cheap and nasty instead please?")
What's the good of a perfect railway line if it never gets built? What happened to the capacity argument? There is likely a good optimum between the cheapest and most expensive possible for capacity and speed. We could all fly around in supersonic aircraft, but there's a reason we don't.
It's getting built! Large sections of it are nearly finished!
Quite a lot of the cost is the NIMBY appeasement mentioned upthread. Something like a quarter of the line will be in tunnels. Making a slower line wouldn't make that any cheaper.
Connections to HS1/Europe, and to Leeds, Golborne, East Midlands, Manchester and finally even Crewe have all been cancelled so now extra expenditures will focus instead on Euston Station. That's not the large section people were interested in riding. Perhaps Old Oak Common should instead have been tunnelled the same distance through to Waterloo International (whose international platforms are now deleted).
The international platforms are not deleted! They were brought back into use from 2018-2019 to serve the Windsor Lines, which includes the service to Reading - platforms 20-24. That somewhat reduces the congestion at Waterloo; the station throat limits adding more services.
The extension to Euston was supposed to have 11 platforms. Even the reduced scope now being implemented is 6 platforms, I believe. All 11 were required to handle the eastern leg of HS2 [providing bypass capacity for the East Coast Main Line out of King's Cross and the Midland Main Line out of St Pancras], and services to Scotland and Manchester [bypassing the West Coast Main Line from Euston's classic platforms].
steam is great technology - it is still used in power plants today. The only reason diesel replaced it was labor cost which made up for the loss in fuel efficiency.
The high speed lets you build the Y shape to serve London to both north east and north west, as well as cross country journeys from Birmingham to the north east with the minimum amount of new track. With more standard rail lines you'd need to build a lot more. Plus there's many other benefits to high speed.
If you’re building a new rail line you might as well make it high speed. The problem is that a political decision was made to tunnel through the Cotswolds to minimise local impact because a lot of rich and influential people live there.
It would have been cheaper if we hadn't done so much tunnelling.
No this is just a typical media nonsense that is spread by idiots who don't know anything.
> If they'd put in another standard rail line instead
That would be crazy. In order to be a viable line to go from Midlands to London and reduce capacity, it would have to be at the very, very minimum as fast as that line goes today. So you are going to build a high-speed line of some sort anyway.
And that means maybe you can be a bit more adaptive to the terrain, but that also leads to more distance and thus more kilometers of line that has to be build.
A huge amount of the cost is simply buying the land, building the tunnels and bridges, putting up the electricity wires and so on. All that you would have to do anyway.
So basically at the very minimum you would need to build a 200km/h line, and nobody serious would even consider that. A 250km/h is the only reasonable 'lets safe money choice'. Going to a 300-350km/h line is going to be more expensive, but likely only by a few %, maybe 10%. But you would lose a huge amount of the benefit, as tons of study show time is a massive important to use.
So if you actually take into account future income from the line, building it to a lower standard would have been insanely stupid.
> taken up much less space
This is just straight up factually wrong. If you want to save money by changing alignment, you need more space, not less.
> would have been much cheaper
As I pointed out, much is simply wrong here.
> would have caused less disruption
Building would have more disruption and overall there would be more disruption in general.
> would have had a clearer business case
The business case, would be much much worse.
The people making that argument somehow think that you could build some rural 160km/h rail line and still get 90% of the benefit. Yet somehow no country who analysis this beliefs this and pretty much every single rail expert in the world doesn't agree with it either.
So the question you have to ask yourself do you want to believe the designer of HS2, most experts in rail technology or a bunch of anti-infrastructure activists?