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Why are people opposed to HS2? (And other HS2 discussion)

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Bald Rick

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Thanks, but that wasn't what I meant. I wasn't thinking about scheduled stops, I was thinking more about safety in the event of an emergency. I would assume that, if a train derails or has some accident causing it to come to a very sudden stop, then an absolute priority is that the train behind must be able to stop in time to avoid a collision. Since it's going to take a little time for the signalling system to inform the train behind that it needs to stop, then at 90s intervals, the train behind is presumably going to have less than 90s to actually stop. I can believe that a train going at 50mph could probably stop in time in those circumstances. I'm struggling to believe that a train going at 125mph could stop in time. But you seem to be saying that 90s headways would work up to that speed?

Ah I see. Yes a train at 125mph can easily stop in 90seconds. Under a minute in fact, at full service braking, and about 45 seconds at emergency braking.

It’s easy to measure technical headway from your sofa. Look at Open Train Times maps, find a stretch of line where trains should always be running at linespeed, and measure the time from when a train steps past one signal, until that signal is displaying a green aspect again. (Not green on OTT, but actually green, for example on the WCML fast lines a signal will usually be showing green when the 2 signals ahead of it are also showing proceed aspects, also shown green in OTT).

I just measured 1H07, and the technical headway at Hanslope is 75 seconds.
 
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miami

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Or we have more people home-based and cut the commuting down as above.

But that doesn't happen. You and I are exceptions. I only get away with it due to the style of work that I do.

(Heating doesn't apply to me -- the house is so warm that I've got the window open)

1. double deck trains - yes I understand the loading guage issue

So not possible

> 2. replace trackside signalling with dynamic on train signalling - if you can platoon trucks, why not trains

Very minor improvements

> 3. improve station functionaility - make it easier to get on trains, new London Bridge is an example of 'access all platforms' from many points
Reducing dwell time? You'd need new stock as well. Is dwell time really a problem at places like Milton Keynes or Hemel Hempsted?

> 4. more trains dividing or combining on route - effectively ensuring every train at terminal is full length and full
And if one of the trains is delayed? Imagine turning the Manchester-Cardiff service into a cross country one operated by voyagers, and getting two voyagers to join at crewe on the way into Manchester. What happens when there's a delay at Hereford? Or Oxford? A problem with a level crossing at Aberystwith could cause a delay to a train at Reading.

The network is already fragile enough

> 5. Pricing - needs to be more dynamic - something around a 'cost plus' basis, for example travel on a train out of Euston am. base fare £X, but each train is above or below that price
You want to charge even more? All increasing costs does is cause people to use other means to travel.

> 6. more station bypass lines where you need them, basically making the current inflexibility of fast and slow lines redendant
Like a bypass of stations where express trains don't stop? Say places like Watford, Milton Keynes, Rugby, Tamworth, etc?

Would you build these extra tracks through the middle of the towns they don't stop at, or would you route them away from the towns?
 

DynamicSpirit

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Ah I see. Yes a train at 125mph can easily stop in 90seconds. Under a minute in fact, at full service braking, and about 45 seconds at emergency braking.

Ah thanks. That answers my question nicely. So on a quick calculation, assuming uniform deceleration, at emergency braking, a train going at 125 mph can stop in about 3/4 mile. And at full service braking in just under a mile. That seems quite impressive.
 

hwl

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If capacity is the real issue, which I think it is, I still sense that the capacity options have not been given full consideration. Capacity is not a train issue, it is a system issue. In otherwords how can you add capacity to the whole system? this has to be a combination of technology, information, pricing and management. So, what might add capacity?

1. double deck trains - yes I understand the loading guage issue
2. replace trackside signalling with dynamic on train signalling - if you can platoon trucks, why not trains
3. improve station functionaility - make it easier to get on trains, new London Bridge is an example of 'access all platforms' from many points
4. more trains dividing or combining on route - effectively ensuring every train at terminal is full length and full
5. pricing - needs to be more dynamic - something around a 'cost plus' basis, for example travel on a train out of Euston am. base fare £X, but each train is above or below that price
6. more station bypass lines where you need them, basically making the current inflexibility of fast and slow lines redundant

I appreciate this is not a comprehensive list, but applying a systems thinking to more than just one line East Coast, Midland, West Coast and via Banbury might just make a considerable difference?

Access to work whilst on the train making journey time less important? LESS important, reliability and capacity need to be addressed...but please can we consider the Swiss approach, as well we as the French one?

Most of those were (15 years ago) - the conclusion was a new high speed line was a better alternative
 

DynamicSpirit

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Most of those were (15 years ago) - the conclusion was a new high speed line was a better alternative

Yes, it does slightly amuse me the way so many of the people opposed to HS2 don't seem to consider the possibility that most of the alternatives people come up with would have actually been seriously considered in the early planning stages, and rejected for good reasons.
 

Yindee8191

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Increased splitting and joining was tried in the new LNWR timetable... and look how well that went.
 

MarkyT

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Increased splitting and joining was tried in the new LNWR timetable... and look how well that went.
It can be done reliably if planned and resourced properly. E.g.
1. Have at least a small crew depot at the split/join location so there's the possibility of spare staff being available and opportunity to replan duties on the fly.
2. Always do it on a dedicated platform that can be bypassed by other trains if things go wrong.
3. Never combine it with over ambitiously short turnround layovers at termini.
4. Have clear passenger focussed strategies to deal with what happens when one portion doesn't turn up on time.
Splitting and joining is a key operational strategy for HS2, as some of the classic network routes will not be able to handle full 400m length trains throughout.
 

miami

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Why is there so much effort being put by some people into avoiding building new track?
 

Bletchleyite

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Increased splitting and joining was tried in the new LNWR timetable... and look how well that went.

LM always did a lot of that and it was reliable enough. The primary problems with LNR are not that, though removing it will help. The problems are:-

- Inter-worked staff and unit diagrams, so disruption in Liverpool knocks onto a Tring stopper, say. The staff diagrams have caused more issues than the stock ones - very often there's a unit sat there blocking a platform (so more knock-on) waiting for crew.
- Insufficient layovers
- Inadequate quantities of staff and stock.

The May timetable is set to improve the first two (plus removing the splits/joins other than adding/removing units at Northampton), though until more stock shows up it will probably be at the expense of shorter formations.

So splitting and joining is not a fundamental problem, and I believe it is indeed planned in the HS2 timetable.
 
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Geezertronic

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Ah thanks. That answers my question nicely. So on a quick calculation, assuming uniform deceleration, at emergency braking, a train going at 125 mph can stop in about 3/4 mile. And at full service braking in just under a mile. That seems quite impressive.

Is the bolded bit 3 quarters of a mile or 3 to 4 miles?
 

D365

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Why is there so much effort being put by some people into avoiding building new track?

New track is ok as long as it's being built on former Victorian alignments. I'm sure EWR Bedford-Cambridge has already caused some outrage.
 

MarkyT

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Here is a little sheet I just prepared to show how headway TIME remains remarkably constant over speed for a 9% braked train, which represents most modern passenger stock. This is because, although safe spacing distance extends with rising speed, it is covered more quickly as that speed increases. Note the constant sum used for sighting, overlap and train length (1000m) dominates headway values at very low speeds as it is much LONGER than the braking distance itself.
headway-appx-C.jpg
 
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Glenn1969

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Do we have any idea when a decision will be announced. It was supposed to be imminent last Wednesday but I know a week is a long time in politics !
 

Neen Sollars

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Do we have any idea when a decision will be announced. It was supposed to be imminent last Wednesday but I know a week is a long time in politics !

Week commencing 9/2/2020, so next week apparently. I searched for HS2 latest news, and an article appeared from the Daily Mail saying the latest cost estimate had now risen to £150 billion. The PM has already acknowledged that HS2 management are a shambles, so it really would beggar belief if he signed this project off.
 

Glenn1969

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But he also told a reporter this week that if you are in a hole as big as HS2 the best thing to do is keep digging. Which makes me think he will sign it off.
 

BigCj34

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Do we have any idea when a decision will be announced. It was supposed to be imminent last Wednesday but I know a week is a long time in politics !

The Guardian seem to have editorially supported it, was wondering where they swayed on the project.
 

jfowkes

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An estimate from who?

From the article:

Today the TaxPayers Alliance reiterated its opinion that it is too expensive and should be abandoned.

The estimated worst-case cost of HS2 is currently estimated at £106billion, but the TPA suggested it could eventually reach £150billion.

So, the Taxpayers Alliance, that bastion of openness and transparency who are definitely not biased at all towards scrapping HS2.
 

MarkyT

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From the article:
So, the Taxpayers Alliance, that bastion of openness and transparency who are definitely not biased at all towards scrapping HS2.
Oh yes, the so-called 'grass roots' think tank and lobbying organisation funded darkly by offshore billionaire airline and petroleum interests among others. And if anyone feels aggrieved by these baseless accusations, reveal their true funding sources and I'll happily retract...
 

DynamicSpirit

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Here is a little sheet I just prepared to show how headway TIME remains remarkably constant over speed for a 9% braked train, which represents most modern passenger stock. This is because, although safe spacing distance extends with rising speed, it is covered more quickly as that speed increases. Note the constant sum used for sighting, overlap and train length (1000m) dominates headway values at very low speeds as it is much shorter than the braking distance itself.
View attachment 73521

Thanks, that's interesting. One thing that struck me looking at those figures is that, I'd have expected braking distance to go as speed-squared, but the table seems to show it increasing at a slightly smaller rate than that. That would seem to imply braking deceleration isn't constant (which is what you'd expect if the brakes exert a constant force), but is slightly greater at higher speeds. If it's not going too far off topic, what's the reason for that?
 

HSTEd

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Thanks, that's interesting. One thing that struck me looking at those figures is that, I'd have expected braking distance to go as speed-squared, but the table seems to show it increasing at a slightly smaller rate than that. That would seem to imply braking deceleration isn't constant (which is what you'd expect if the brakes exert a constant force), but is slightly greater at higher speeds. If it's not going too far off topic, what's the reason for that?

Well remember we also have to account for aerodynamic effects.
Trains that are moving faster will tend to have greater deceleration from aerodynamic drag.

Indeed at least two experimental Japanese test trains have fitted full blown air brakes.
 

Bald Rick

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Here is a little sheet I just prepared to show how headway TIME remains remarkably constant over speed for a 9% braked train, which represents most modern passenger stock. This is because, although safe spacing distance extends with rising speed, it is covered more quickly as that speed increases. Note the constant sum used for sighting, overlap and train length (1000m) dominates headway values at very low speeds as it is much shorter than the braking distance itself.
View attachment 73521

Thanks for that Mark, a perfect illustration of my point!

Thanks, that's interesting. One thing that struck me looking at those figures is that, I'd have expected braking distance to go as speed-squared, but the table seems to show it increasing at a slightly smaller rate than that. That would seem to imply braking deceleration isn't constant (which is what you'd expect if the brakes exert a constant force), but is slightly greater at higher speeds. If it's not going too far off topic, what's the reason for that?

Part of it is also the distance taken from sighting the cautionary aspect to the brakes being at full retardation. That is proportional to speed, not speed squared; around 2-3 seconds is allowed for driver reaction+driver applying the brake+brake responding.
 

Sad Sprinter

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Good point. You know, the jobs don't always HAVE to be in London. Until some jobs are transferred north, then all that will happen is jobs will be sucked into London. Note that in a survey today London people are most supportive of HS2 - and for very good reason. Jobs can be relocated via grants for firms to move to Birmingham, Coventry etc in Midlands, but also the economic wastelands of the north east, Lancashire and parts of Yorkshire. Remember some people commute long distances TO London, if the jobs are attractive enough and travel times / costs reasonable, they might even travel to say Barnsley! But they can't at present as there are few really good jobs and much of the rail service north of Birmingham is desperately slow and overcrowded. Typical Huddersfield to Barnsley 18.9 miles by road, around 50 minutes by rail - one service per hour.

Indeed why can't some of the relocated jobs be in Milton Keynes?

The macho nonsense of having 09.00 meetings in London is in many cases unnecessary and if essential an overnight stay in London easy enough to arrange. Staggered working hours would smooth the capacity issues.

Off topic-but isn’t it better to create new jobs in the north than forcing them out of London?
 

jfollows

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The Economist has changed its mind and now advocates HS2 on the basis that, although the BCR figures don't necessarily stack up, the long-term benefits of big transport projects tend to be underestimated (Jubilee line, as an example) and because climate change will put a premium on carbon efficiency in the future.
Investing in rail
Why HS2 should go ahead

Britain is poised to decide whether to build an expensive new railway

Leaders

Feb 6th 2020
For the country that invented railways, Britain has shown remarkably little interest in them lately. New networks have been built around Europe in the past few decades, but the only significant stretch of track laid in Britain in a century is the 67-mile (107km) hs1 railway that links London to the Channel Tunnel. Indeed, the country has half as much track as it had in 1963. Yet while Britain has an almost American reluctance to invest in railways, its commuting patterns are European: 10% of journeys are by rail, compared with 9% in Germany and less than 1% in America. The result is a lot of angry commuters.

Britain’s big problem is that, because it has built no new high-speed lines, it runs fast intercity trains on the same track as slow commuter ones. Long gaps have to be left between slow and express trains. The need to make way for high-speed trains thus limits the number of commuter services, and vice versa.

Eight years ago, the government decided to rectify this by building a new 345-mile railway from London to the north of England. Though branded as High Speed 2, its principal job was to boost capacity rather than speed. At the time, this newspaper argued against it. Although we supported the idea of investment in train capacity, we believed that there were better projects to spend money on than hs2.

Spooked by the costs—now put at around £100bn, against an original estimate of £42bn—and by the fury of 21 Tory mps whose rural constituencies the track would slice through, the government is considering cancelling the project. A final decision was due as The Economist went to press. We now believe the line should go ahead—not because £8bn has already been spent, but because the circumstances have changed.

Rail is an increasingly important part of the transport mix. Climate change is putting a premium on carbon-efficiency. At the same time, passenger numbers have exceeded forecasts. The government had expected passenger volumes to increase by 17-21% in the decade from 2011; actually, they were up by 24% within just seven years and are expected to go on growing at a similar clip. The costs of other, cheaper ways to boost capacity, such as double-decker carriages and longer trains, have increased, along with the cost of engineering wider tracks and higher tunnels, and of buying more property around stations. Meanwhile interest rates are so low these days that the government can borrow long-term for virtually nothing.

The benefit-to-cost ratio (bcr) calculated for hs2, at around one, is hardly a ringing endorsement. But just as the costs of big transport projects are often underestimated, so are their long-term benefits. The extension to London’s Jubilee tube line, for instance, was approved with a bcr of less than one, but recent analysis suggests that it has been more like 1.75. And that includes only the revenues that go directly to the railway, not the economic consequences of the revival of London’s Docklands area, which the tube line made possible.

The main point of hs2, similarly, is its impact on the cities and towns along its route and beyond. Boris Johnson, the prime minister, is on a mission to boost growth in northern and western areas left behind by the country’s lopsided, London-centred pattern of growth. On its own hs2 won’t make that happen, but doing so without a new railway would be tough. The success of the “Northern Powerhouse” rail scheme, to link the north’s big towns, depends on it.

This is a tricky decision for Mr Johnson. It will be the biggest financial call of his time in office. His party is divided over the issue. hs2 will dog his premiership if it goes wrong. But if he wants his vision of Britain to work, he needs it.
 
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