The only way to make HS2 cheaper? Build HS3

[grove]

A short but perceptive assessment https://www.cityam.com/the-only-way-to-make-hs2-cheaper-build-hs3/

 

[SynthD]

It’s wrong. HS2 is training up people that could do HS3, Crossrail2, NPR, BLE or, like with Crossrail1, a football stadium. HS2 is creating jobs in other companies that are also not strictly tied to high speed rail. The idea that promising future work will enable greater investment is shaky, considering how little promises mean over those timescales. Truss is the only PM of the last 30 years not to have fingerprints on the project (except cost of loans?).

 

[grove]

It’s wrong. HS2 is training up people that could do HS3, Crossrail2, NPR, BLE or, like with Crossrail1, a football stadium. HS2 is creating jobs in other companies that are also not strictly tied to high speed rail. The idea that promising future work will enable greater investment is shaky, considering how little promises mean over those timescales. Truss is the only PM of the last 30 years not to have fingerprints on the project (except cost of loans?).

Yes, the support, particularly financially, is at best flaky for some of these projects.

 

[Tomos y Tanc]

Yes, the support, particularly financially, is at best flaky for some of these projects.

The analogy with the Ford production line is just bonkers. Infrastructure and manufactured goods are entirely different things. Whichever child wrote that article really needs to bone-up before his GCSEs.

 

[Norm_D_Ploom]

There is some merit in the argument though, the best way to ensure that the mistakes of HS2 are not repeated would be to learn from them when building HS3, whilst they are still fresh in the memory.

Whilst I can see the argument I don't agree with the dig about capacity/ high speed, although aren't the ICE around 250/ 275 k so perhaps that might have been sufficient in respect of top speed, although it wouldn't have made a great deal of difference to the output cost given the amount of tunnel.

End of the day, for multiple reasons, the country hasn't got a pot to piss in so we won't be building HS3 anytime soon.

 

[HSTEd]

Whilst I can see the argument I don't agree with the dig about capacity/ high speed, although aren't the ICE around 250/ 275 k so perhaps that might have been sufficient in respect of top speed, although it wouldn't have made a great deal of difference to the output cost given the amount of tunnel.

Lowering the speed requirement would have relaxed many of the complex (and very expensive) technological solutions required for those tunnels though.
At 300kph with the given cross sections, the humongous 100m tunnel hoods, sophisticated active ventilation systems and the like could all have been jettisoned.

Indeed, it is not unlikely that boring bigger tunnels would have turned out cheaper given the amount of extra stuff that could have been dispensed with.

 

[Norm_D_Ploom]

Lowering the speed requirement would have relaxed many of the complex (and very expensive) technological solutions required for those tunnels though.
At 300kph with the given cross sections, the humongous 100m tunnel hoods, sophisticated active ventilation systems and the like could all have been jettisoned.

Indeed, it is not unlikely that boring bigger tunnels would have turned out cheaper given the amount of extra stuff that could have been dispensed with.

It would still be a tunnel though, which by its very nature is more expensive than building in the open.

 

[HSTEd]

It would still be a tunnel though, which by its very nature is more expensive than building in the open.

It is somewhat, but not as much as might once have been expected.

Tunnels and viaducts have the advantage that they don't interact that much with stuff on the surface.
Just look at the sprawling works required for road and utility diverisons on the open air sections, this is one of the reasons that tunnel and viaduct fractions on railways and other linear infrastructure have been increasing with time. Even in places where aesthetic drivers are less important like China.

 

[JamesT]

The article suggests it would have been cheaper to go and ask the French or Germans to just build a replica of their current high speed lines.
But my understanding is that HS2 did consult various countries already running HS rail and they recommended aiming for a high speed to start with. It’s not as if HS2 is wildly out compared to current trains, the Chinese have been running at 350kph since 2008.

 

[FMerrymon]

The article suggests it would have been cheaper to go and ask the French or Germans to just build a replica of their current high speed lines.
But my understanding is that HS2 did consult various countries already running HS rail and they recommended aiming for a high speed to start with. It’s not as if HS2 is wildly out compared to current trains, the Chinese have been running at 350kph since 2008.

That's right, apparently the president of sncf recommended it https://publications.parliament.uk/pa/cm201012/cmselect/cmtran/1185/1185.pdf.

Alignment speed of hs2 is not that much different from, or the same as, LGV lines and Italian lines. In terms of tunnels, no hs2 bored tunnel has a higher speed than 200mph, so LGV standard. Ive read that some LGV tunnels are good enough for 220mph operation too.

 

[HSTEd]

HS2s tunnels are very different in conception than LGV tunnels, they were shrink wrapped to the smallest possible diameter in claimed pursuit of "sustainability". HS2 even wrote a blog about how they had saved 1.5 million cubic metres of excavation... in exchange for all the technical problems they created. Everyone else in the world has been making tunnels bigger with time as it reduces the challenges on construction and operation.

 

[FMerrymon]

Saverne tunnel is 8.9m diameter https://en.wikipedia.org/wiki/Saverne_Tunnel
Chiltern tunnel is 9.1m diameter.
This doesnt look like a massive difference to me, with the hs2 tunnel the larger of the two.

 

[HSTEd]

Saverne tunnel is 8.9m diameter https://en.wikipedia.org/wiki/Saverne_Tunnel
Chiltern tunnel is 9.1m diameter.
This doesnt look like a massive difference to me, with the hs2 tunnel the larger of the two.

Comparing a 4km tunnel with a 16km tunnel is not really comparing apples to apples. The pressure effects that are limiting on the diameter become more severe as length increases.

A 4km tunnel is only a handful number of times the length of the train.

The two tunnels have comparable cross sections on the order of ~55 square metres, depending on how you measure it.

EDIT:

THis is why the chiltern tunnel is being provided with 220m long concrete hoods on each end and the Saverne tunnel is not.

EDIT #2:

I dug out the HS2 website blog post which contains:

Taking the train speed into consideration, the cross-sectional areas of HS2 tunnels are in general smaller than in other countries, as illustrated in Figure 2. This is a result of a value-engineering process aiming towards an economic tunnel design that accounts for aerodynamic considerations and explains why HS2 cannot simply adopt aerodynamic solutions from HSR systems in Europe or Asia. In total for the Phase One tunnels, using the tunnel sizes in Table 1 rather than the international norms in Figure 2 saves of the order of 1.5Mm3 of tunnel volume, resulting in significant economic and environmental benefits.

1.5 million cubic metres of tunnel volume is unlikely to be a substantial cost saving given that the only costs for the bigger tunnel will be marginally increased mass of tunnel segments, marginally increased spoil disposal cost and marginally increased purchase cost of the TBM. Against the cost of giant tunnel hoods all over the place, sophisticated ventilation damping at the intervention shafts etc.

 

[Mgameing123]

HS2s tunnels are very different in conception than LGV tunnels, they were shrink wrapped to the smallest possible diameter in claimed pursuit of "sustainability". HS2 even wrote a blog about how they had saved 1.5 million cubic metres of excavation... in exchange for all the technical problems they created. Everyone else in the world has been making tunnels bigger with time as it reduces the challenges on construction and operation.

Please atleast tell me that HS2 is UIC GC compliant!

 

[SynthD]

Please atleast tell me that HS2 is UIC GC compliant!

The new parts are. The captive trains will be GC sized, if they ever exist.

 

[zwk500]

Please atleast tell me that HS2 is UIC GC compliant!

HS2 is being built to UIC GC loading/structure gauge except for the platforms which will be at a level boarding but non-standard height of 1200mm.
Other threads have suggested that the platforms will be far enough from the rail to be compliant with UIC GC and that classic-compatible stock will have gap fillers to compensate, but I haven't seen the full technical specs.