What does "need to be" mean?Again, why dig tunnels bigger than they need to be? The fact that you can do something doesn't mean that you must.
Why would HS2 tunnels "need" to be 'Continental' gauge?
What does "need to be" mean?Again, why dig tunnels bigger than they need to be? The fact that you can do something doesn't mean that you must.
What does "need to be" mean?
Why would HS2 tunnels "need" to be 'Continental' gauge?
What does "need to be" mean?
Why would HS2 tunnels "need" to be 'Continental' gauge?
What does "need to be" mean?
Why would HS2 tunnels "need" to be 'Continental' gauge?
And/or specially shaped tunnel portals to avoid high pressure pulses (and sonic booms).You can get away with narrower tunnels for a certain speed - but it requires things like Japanese style aerodynamic noses.
The 'Continental' size train is supposed to have a capacity up to 550 seats.It doesn't need to be to continental gauge, but again (like the speed question) what do you gain by doing so at what cost?
The to you gain is being able to buy "off the peg" high speed trains with the option for a lot more capacity or at the very least a lot more comfort of there's more extra capacity.
How much is "Not a lot more"?What does it cost you? Not a lot more.
The difference in cross-sectional area between domestic and continental train standards is not enough to make any noticeable difference in minimum tunnel cost and complexity, especially when there would be the same requirements for emergency and maintenance walkways.
HS2 tunnels for the most part do actually need to be wide enough for continental trains. High speed trains running through tunnels create a pressure wave ahead of them which gets worse with a smaller diameter, or a larger train cross-section.
HS2 trains will get up to 205km/h between Euston and Old Oak Common and at that speed, an approximate 7m tunnel diameter is required.
Theres even been mention that we dont need HS2 because of driverless cars
Are HS2 going to buy off the peg trains?
If the difference in cross-sectional area between domestic and continental train standards is not much, there can't be much difference in capacity.
Different HS2 tunnels have different diameters. If "there's not much difference in cost" / "TBM tunnels are cheap and easy", why aren't all the tunnels built to the largest size?
If the difference in cross-sectional area between domestic and continental train standards is not much, there can't be much difference in capacity.
Different HS2 tunnels have different diameters. If "there's not much difference in cost" / "TBM tunnels are cheap and easy", why aren't all the tunnels built to the largest size?
Where would be the sense in accelerating up to 205 km/h inbetween station calls just 5 miles apart, or whatever it is?
HS2 and similar lines may well be the only rail left in the majority of the country in 50 years time, and I welcome that.
And that's why I think, in 50 years time, there would not have been an HS2 at all. Because as the 2020 general election comes into focus, 2020 vision will appear in the minds of all politicians who realise that it's far better to deliver promises on the doorsteps than visions of the future.
Too late for that, enabling works have already started.I have a sneaking suspicion that HS2 will be just an idea, never implemented, in 50 years time, an idea stopped at the last minute with not one screw, not one drill, not one ceremonial ribbon used in action.
Phase 1 has recently received Royal Assent, a lot of the contracts have already been signed (and would be very costly to get out of) and construction will begin later this year. The major political parties support it, as do the majority of MPs. There's no political appetite to stop it at the last minute, in fact it's too late anyway, never mind 2020.Neither you nor I have any clue about 50 years hence, but I have a sneaking suspicion that HS2 will be just an idea, never implemented, in 50 years time, an idea stopped at the last minute with not one screw, not one drill, not one ceremonial ribbon used in action.
And that's why I think, in 50 years time, there would not have been an HS2 at all. Because as the 2020 general election comes into focus, 2020 vision will appear in the minds of all politicians who realise that it's far better to deliver promises on the doorsteps than visions of the future.
Exactly!Too late for that, enabling works have already started.
Too late for that, enabling works have already started.
Needless to say, I am anti-HS2, always have been, always will be, will never budge from that position.
This seems to be a strange position to hold. I can see you disagree with the arguments put forward in favour of HS2. I happen to agree with them and favour HS2. However, the arguments are all based on what we think is going to happen in the future. We can all make our best guess about whether or not HS2 will or won't be a success, but ultimately the proof of the pudding will be in the eating.
If, once HS2 is built, virtually nobody uses it, then I would have to change my mind in the face of the facts. At present I think that scenario is highly unlikely, but if it happened I would have to admit that I was wrong. However, if it turns into a roaring success, the trains are full and there is massive modal shift to rail, not just to London but to all the other major cities HS2 serves, and if we see consequent major improvements to commuter and regional services using the freed up capacity on the existing network, then surely you would have to reassess your position? Just to clarify, it's clear that you believe this scenario will not happen, but if it did, if the facts changed, would you not change your mind?
That might have been tongue in cheek, but in case it wasn't increasing the capacity of the existing road network is probably the biggest advantage of autonomous road vehicles. Presuming that they have some kind of short-range wireless communications setup they would be able to drive much closer together than humans can manage, much more safely since the reaction time would be milliseconds.
Reaction time you will save, but rubber on wet tarmac sets the physical stopping distance, unless you are suggesting that rear ending will become acceptable.
If, once HS2 is built, virtually nobody uses it, then I would have to change my mind in the face of the facts.
This arguement will go round and round in circles for a lot longer. My own fear is that we will end up with phase 1, with a lot of the promised environmental mitigation dropped to save money, and then the rest will be cut.
Reaction time can be greater than actual stopping distance.
But there isn't the need for the same separation because if the front car has to stop, the middle and rear cars will also know to stop. The risk is only greater if the front car suffered a sudden catastrophic mechanical failure (or hit an obstruction) and stopped dead.
That kind of accident is rare though. The fact is that inter-vehicle communication will allow reduced separation. Even a small reduction can make a massive difference to capacity.I once attended a road traffic accident (yes they were called accidents in those days) where a large ingot fell off a lorry.
The ingot stopped dead but the following car didn't.
And that has to be allowed for. Imagine how much rail capacity we could generate if we were allowed to run trains on that basis, but then again railways have to be safe.
I once attended a road traffic accident (yes they were called accidents in those days) where a large ingot fell off a lorry.
The ingot stopped dead but the following car didn't.
I must admit I do think the railway could save money, be a *little* less safe and still be acceptable (I won't mention it here directly, but a key method of achieving this is being debated hotly on other threads). I don't fear travelling on PKP (say) despite their record being a bit less good than here. If that then went on fare reductions and capacity, lives would be saved overall as more would switch from the relatively dangerous option of car travel.
Yes, that's the exception. But if one life is claimed from that, but 20 lives are saved by the removal of human error, there's still an overall gain. But people seem to want 100% safety, which can never be (economically) achieved.
This is getting off-topic here, but I don't believe it at all acceptable to say that the level of safety and security can be reduced simply for the sake of cost-cutting. Human lives should not be measured in currency, and even if "100% safety" is not achievable, doesn't mean that we shouldn't be taking every measure in our power to eliminate all potential risks. Britain's railway network is statistically one of the safest in the world, after all.
I don't think that is the suggestion. We need to recognise that safety has a cost and not be afraid to ask the question if a particular measure is justified on the cost:benefit basis.This is getting off-topic here, but I don't believe it at all acceptable to say that the level of safety and security can be reduced simply for the sake of cost-cutting.
My own fear is that we will end up with phase 1, with a lot of the promised environmental mitigation dropped to save money
That won't happen, as people won't give up using the WCML any time soon, and it will basically just be another pair of (super-)fast lines for the WCML.
Think of it being as more like the SBB Neubaustrecken, not the French "completely new line" model. You don't choose to use HS2, if you take the train from London to Manchester (or whatever) the train will simply be routed onto it. Only in the context of London-Birmingham will it be in any way like the French model, and that's only really a coincidence to the project.
They probably made an error selling it based on journey time cuts, it should have been sold on what it will enable on the WCML.