Let me be the first to state that DB should concentrate on having every day normal trains run on time without being cancelled. They have somehow gained a dismal reputation on that point in the past decade, that they most definitely did not have in the nineties (at the time, Italy was the butt of such jokes). This is far more relevant and important for the reputation of a rail network than the max speed you can reach on controlled tests.

Came here to say the same. There's nothing wrong with faster services, but ask most travellers, especially commuters, and I bet they'd prefer trains that depart and arrive on time than have a shorter but unpredictable journeys. if you're trying to improve any process then the first step is to get what you've got running reliably and consistently before you start tweaking it.

This is pretty much the Swiss model, where trains are run slowly with slack in the timetable to make up time.

They also ban late-running German trains from their network to avoid knock-on effects!

You can have both: The UK trains I use combine sloth-like speeds with unreliability.

' ...combine sloth-like speeds with unreliability... '

That combination can, and does, get extremely expensive.

(Actually, we travelled by train into our local city a few days ago and it was a very good service, if a tad on the expensive side.

There was only one announcement of a delay to another service caused by a broken-down train.)

The UK actually has the fastest slow trains in the world. As well as the fastest steam train and fastest diesel.

Our fast trains are not very fast, other than the French ones on LGV Nord / HS1; but we do have the highest average train speed.

How fast it is economic to have a train run depends on the distance you expect it to travel. Britain is small compared to France or Germany; Switzerland is even smaller, and distinctly knobbly.

The design of the HS2 was predicated on the longest possible domestic run being from London to Glasgow or Edinburgh. Once you are in Scotland speeds are necessarily lower. What killed the HS2 was that BR expected to run it through the Channel Tunnel, but no-one told RTZ, who were building(?) the tunnel. The shock waves of a 400kmph train entering and running though a tunnel would shatter the passengers' ear drums; once the train had to slow down to around 120kmph the whole thing became uneconomic.

BTW I was present when the mismatch of expectations came to light. It was at a Sunday afternoon tea, not a formal review meeting.

Proper train nose design should help tunnel boom problems tremendously https://www.jrpass.com/blog/why-shinkansen-bullet-trains-no-longer-look-like-a-bullet. Probably still not allowed to enter at 400km/h, but shinkansen as far as I can find runs 260 km/h into tunnels. Which is still damn fast

It's all very well for the Chinese to shoot their tiny test vehicle (1.1 tonnes, apparently, half the weight of a Land Rover Discovery) down a 1 km test track and claim a world speed record, but a little arithmetic shows acceleration to get to 650 kph in seven seconds is 25.79 m/s, i.e. 2.6 g. There's no way the average traveller is ever going to get on a train that subjects them to those sorts of accelerations.

If we're looking at small things moving quickly on rails, then 2560meters/second would be the record. This was accomplished by something similarly non-passenger-carrying... a rail gun.

Glad to see the Germans match an early tech-demo with an actual rail vehicle on proper track.

Well, it does look like China is giving serious effort to a Hyperloop vacuum style maglev train, under the name T-flight. Given the backing of state resources and apparently serious large scale testing on a reported 60km test track, that might actually come to something (unlike Elon's brain fart) although I doubt that there will ever be a viable economic business case given the vast infrastructure costs.

Came here to say the same. There's nothing wrong with faster services, but ask most travellers, especially commuters, and I bet they'd prefer trains that depart and arrive on time than have a shorter but unpredictable journeys.

Absolutely. It's a shame the messaging over HS2 has been so abysmal, since that's exactly what it was designed to do (since most commuters are on local/regional trains, not long-distance HS services). Raising line speeds on existing lines is always making trouble for yourself down the line (apart from slightly higher speeds as regional lines get out the suburbs and go rural, with longer gaps between stops. Some urban lines don't need to get past 40mph due to frequent stops, but 100-120mph is pretty sensible once you're doing 5-15mile stretches).

Mixed traffic running (local + express) causes all sorts of problems, and a delay in one place can cause knocks nationally.

For instance, Birmingham New Street in the UK was built as a cross-city hub. Mostly through-platforms for local and regional services barreling around the Midlands. But over time it became a national hub as well, hosting London and Glasgow trains.

A Glasgow train parked in a through-platform for half an hour doing turn-around and crew-change blocks 6-8 potential local services (dwell time of 3 minutes and then shooting on). If that trainset goes tech or there's a late departure for some reaosn, that can literally knock on across the UK, blocking arrivals or departures from Plymouth, Nottingham and further.

The new Curzon Street station will lift all the long-distance (London, Scotland, etc) express services away from BNS, which will relieve a huge bottleneck and allow literally dozens of additional local/regional services per hour through BNS, using all that extra capacity on the Cross-City line and the rebuilt University station. Plus more services down to the South-West, Swansea and Aberystwyth.

Alas, because Sunk-it cancelled Phase 2a to Manchester, the long-distance trains out of Curzon will merge back onto the WCML just south of Stafford, so although there can be lots of extra trains across the West Mids, the SW & Wales, and out to Wolverhampton-Shrewsbury, we won't get any extra capacity towards Crewe or Stoke. Nor will we be able to reopen stations like Barlaston, Wedgwood or Norton Bridge, which closed ~2004 not for lack of passengers, but because rising line speeds meant it was impossible to stop local trains there without blocking a

Upvoted, sadly only once

It's a shame the messaging over HS2 has been so abysmal

Yeah. They kept on pushing the "faster trains" bit but that's not the biggest benefit of HS2. More capacity is the real benefit. The WCML (& ECML) are "full" and there's still more demand for services (Passenger & freight) but no-where to put them.

"Yeah. They kept on pushing the "faster trains" bit but that's not the biggest benefit of HS2. More capacity is the real benefit. The WCML (& ECML) are "full" and there's still more demand for services (Passenger & freight) but no-where to put them."

For a definition of full. Government bottled out on the technology to implement moving block signalling that would have given speed and capacity improvements, and that for a circa £4bn increase in costs. Compared to the eye watering financial black hole of HS2 that's chump change.

For a definition of full. Government bottled out on the technology to implement moving block signalling that would have given speed and capacity improvements, and that for a circa £4bn increase in costs. Compared to the eye watering financial black hole of HS2 that's chump change.

There's limited evidence that rolling-block signalling meaningfully increases capacity. It does a bit, but it mostly improves safety and gives signallers a bit of wiggle room. Traffic segregation will open up 4 train paths for local services for every inter-city train lifted onto HS2. RBS isn't going to give you a 300-400% capacity uplift. Like, 30% at most. In some places.

The costs on the WC Route Modernisation were spiralling from £5Bn for the whole thing to >£15Bn, so they pulled rolling-block and reduced the target speed from 140mph to 120mph (because that meant they could use line-side signalling instead of in-cab, which would have come with ETCS).

At the end of the way, the WCML is one of the most complex bits of railway in Europe. Trying to "big bang" a big signalling project like that was always going to end in disaster. They ended up deploying it on the Cambrian line, which is a very simple line, which gave them a chance to actually learn how to install and run it. Although it's overkill on small lines, it's actually easier to roll out there and then build into the trunk once you've got a pool of expertise.

Also, whatever minor capacity increase you do get from rolling-block, you're still running a gimped timetable by leaving massive headways behind slow trains before you can dispatch the next fast train.

There's no getting around the [1]mathematical inevitability of train graphs .

[1] https://rationalwiki.org/wiki/High_Speed_2#Capacity

The problem with local stations is that it allows passengers to get on and off somewhere near their start point and destination and there is one thing that messes up the efficient running of a railway it's passengers with their wants and needs!

"The new Curzon Street station will lift all the long-distance (London, Scotland, etc) express services away from BNS, which will relieve a huge bottleneck and allow literally dozens of additional local/regional services per hour through BNS, using all that extra capacity on the Cross-City line and the rebuilt University station. Plus more services down to the South-West, Swansea and Aberystwyth."

Yeah, and it will keep New Street as a stygian, unfit for purpose shit hole, with the added bonus of having no fast links to London when HS2 opens. Anybody using train services to New Street who wants to connect to London will be faced with a 15 minute walk from New Street (or paying a few quid more for a similar net travel time waiting for and travelling on the grindingly slow trams). Or they could catch the stopping services from New Street to London that take two and a quarter hours. Birmingham had three crap city centre stations, and the HS2 solution was to add a fourth one in a deserted area of post-industrial land well away from where anybody wanted to go to.

More services to Swansea and Aberystwyth? Woohoo! There's diddly squat in the way of passenger traffic from Birmingham to those destinations (annual travel last reporting year New Street to Aberystwyth, 6,854 passengers, Swansea, 4,401 pax). Running more trains where people don't want to go doesn't help. The south west (or cross country) services there is a capacity problem, but little of that's down to capacity limits across Birmingham without multi-billion investment on the southern cross city line. And if they wanted more capacity on the line via Milton Keynes, they should have upgraded the line via Banbury.

What was needed was to spend serious money (the sort of endless billions that HS2 has already committed for a crap faux-fast solution) to sort out a single central Birmingham station that linked in the two (eventually three) routes to London, the local and inter-regional services, in a modern station that serves the people of Birmingham.

Yeah, and it will keep New Street as a stygian, unfit for purpose shit hole, with the added bonus of having no fast links to London when HS2 opens.

It's funny, people decry HS2 as "oh, who wants to get to London 20mins quicker?"

But when you point out that it means you get loads more local trains (most journeys being local/regional), people complain about wanting a (not really that) fast train to London. New Street will become a proper West Mids hub with lots of high-frequency local trains, designed to get people out their cars for short journeys that ought to be a train ride (and would be if there were 4-6 tph instead of 2, because then it would be Tube levels of convenient and you don't even have to think about the timetable - just hop on the next one).

As for location. There's a bunch of work around Moor Street so a number of regional services will come there instead of New Street (further space for local services), which will suit onward travellers. And realistically they're going to end up with a travellator connecting the lot anyway.

More services to Swansea and Aberystwyth? Woohoo! There's diddly squat in the way of passenger traffic from Birmingham to those destinations (annual travel last reporting year New Street to Aberystwyth, 6,854 passengers, Swansea, 4,401 pax).

And why do you think that is? Frequency is freedom. If you have very occasional trains, only the desperate use them - because you have to fit your day around the timetable and a missed connection could be calamitous - especially if the last train leaves relatively early (<8-9pm). Frequent trains drive modal shift. This is not wishful thinking, but basic network effects shown by decades of research.

More to the point, how many people on the Swansea route will have (dis)embarked at Cardiff, or one of the many other intermediate stops? More frequent trains benefit local services - regardless of whether people go all the way from Brum to Plymouth or Swansea, additional services on those routes encourages usage of the intermediate stops.

It's one of the silly things about current rail pricing - people travelling from Stoke or Stafford to London can get CrossCounty (£££) or London-Northwestern (£ but slower).

In France, there wouldn't be a price difference - you'd buy a ticket to London and then get on the next train - and you'd pick the TGV that's going to thump down the LGV obviously. The slow one will get you there (possibly with a couple of changes), but is intended for people making partial journeys - Stone to Tamworth or Rugby to Rugeley. It's only under the asinine UK franchise system where we don't have enough trains, and we haven't invested in Inter-City infrastructure (HSR) where we use pricing to encourage long-distance passengers onto the slow trains as a form of demand-management from the rammed ICE services.

What was needed was to spend serious money (the sort of endless billions that HS2 has already committed for a crap faux-fast solution) to sort out a single central Birmingham station that linked in the two (eventually three) routes to London, the local and inter-regional services, in a modern station that serves the people of Birmingham.

I'd be all for a proper Hauptbahnhof for Brum. I don't disagree. But that ignores the problem that you won't get those extra services without dedicated fast lines. Curzon Street unblocks platform space at New Street. But it also physically removes non-stop services (that currently blow through Coseley, Smethwick, Penkridge, etc without stopping). If the Brum-Wolverhampton-Stafford line is still choked with Glasgow and Manchester-bound trains, you can't run additional local and regional services. And the fastest/cheapest way to do segregation is generally a new HSR line running through (mostly) countryside, because adding another pair of tracks to the line through Wolverhampton would demolish a lot more houses and businesses and ultimately cost a lot more.

Let me be the first to state that DB should concentrate on having every day normal trains run on time without being cancelled.

To be fair, they tend to go hand-in-hand.

Works that raise line speed (re-grading/alignment, relaying track to a higher spec, ironing out sharper bends) tend to improve reliability by virtue of the fact you're doing a bit of a rebuild on them. The higher speed is really a nice side effect. Especially so if they also upgrade signalling, which can give the signallers more headroom in case of contingency/delays (assuming manglement don't just try and cram more trains through instead).

I'm not sure what work is or has been done on that line, but as it's closed until July 12th, it's seemingly been quite a significant closure/maintenance window - not getting possession for a day or two for a PR stunt.

"Let me be the first to state that DB should concentrate on having every day normal trains run on time without being cancelled."

Germany had a guy who made that happen ~90 years ago. It didn't end well.

Nah it's Mussolini who made the trains run on thyme.

Without being cancelled is the crucial part - the statistics show a high percentage of local trains on time, but if you're standing on the platform waiting for one, they are reguarly five minutes late at first, then ten minutes, then 15 minutes, before being "cancelled" for "reasons". The train that was 20 minutes late is thus not late at all, unless you were waiting for it.

A few weeks ago we took a trip through Germany to Kiel (excellent ferry from there to Oslo) which involved in total 8 IC/ICE trains. The most punctual of them was only 15 minutes late, three were cancelled in whole or part, three others were about an hour late. Even on those that ran the seat reservations didn't work out as the carriages/seats had been renumbered. The whole experience was horrible. So I totally agree that they need to concentrate on getting their existing trains running properly.

That after decades of neglect and privatisation they even found a stretch to pull this off is nothing short of amazing. You average German who has had to use DB in the last 10 years, give or take, would only laugh cynically.

Germany has failed to invest in its infrastructure (not just rail) for decades with the result that much of it is crumbling or even unsafe. The money that needs to be spent will dwarf the amounts "saved".

Meanwhile, England (and, on paper, Wales) has invested billions in HS2 and has nothing to show for it.

I don't think the cynicism is confined to Germany.

au contraire.

There is a construction scar that can be seen from space running from the outskirts of London in a vague N.W direction to Brum. Then, a few bits N.E. of brum that will probably never be used unless it is to store the unused HS2 trains before they get sold to places like Mexico (as is happening with HST units)

Oh, and we all have a huge hole in our pockets that was used to pay for this thing.

Just last week a friend travelled by train until it stopped due to a bus hitting a rail bridge. The rail replacement bus took so long to arrive that they eventually continued by train.

Why are busses not fitted with collision detection sensors wired to the brakes like they are in current cars? Before you say busses are older, most of them are relatively new, and iirc trucks had anti lock brakes long before most cars did.

Because adding and/or retrofitting would be hugely expensive compared to the actual costs of a rare event.

On top of that you will likely get so many false positives from overhanging trees and bridges that are high enough for the bus to pass but low enough to trigger the detector that the collision detection would be a liability in its own right.

"Why are busses not fitted with collision detection sensors wired to the brakes like they are in current cars?"

More to the point, why did the bus proceed towards a low bridge? If the driver is paying that little attention they should never be in charge of a passenger vehicle (not even a car)

It's relatively cheap and easy to protect low bridges - fit a "can opener" in front of them - but for some reason this is rarely done

Yes, such devices utterly trash the high vehicle but that's exactly what they're intended to do. Mandatory minimum disqualification of drivers would help a lot too - people are best persuaded when it affects their wallet

The can opener would probably punish the passengers more than the bus driver. Passengers arriving looking like a boiled egg with the top removed wouldn't do wonders to get drivers out of their cars...

Why did the bus proceed towards a low bridge?

Most bus routes wouldn't pass under bridges which are too low for obvious reasons so it's either a double-decker being run on a single-decker route or the bus has gone off-piste because or roadworks, other diversion, or a driver has simply got lost, taken the wrong turn on an unfamiliar route.

As for not stopping before collision; that often proves to be a single-decker driver forgetting he's driving a double-decker, poor judgement through stress of not knowing where the fuck they are, and there have been cases of stated height in the cabin being incorrect, or bridge height not as correct as it could be, especially if arched.

I heard one tale of a road being resurfaced making all the difference between success and front page news. Someone had to be the first to discover that problem.

And we have to note it is a rather rare event.

A long time ago my dad, a bus driver, ripped off the A/C unit from a bus while driving under a bridge. It was fine with the old ones without aircon, not so much with the stuff (perhaps just condenser and fans, not sure) installed on top, about 30cm thick.

He had a few pax help to load it in the luggage compartment and kept going.

The move towards uber-style employment of drivers on long-distance coach routes often causes problems, not least because they may be using sat navs that are not designed for buses. I've sat in one with the driver, clearly visiting somewhere for the first time, merrily drove into the bus station via the exit.

Still, they are cheap. Which is all that matters for many.

[1]YOU CAN’T CUT BACK ON FUNDING! YOU WILL REGRET THIS!

[1] https://i.kym-cdn.com/entries/icons/original/000/005/703/sc2k_b.png

Meanwhile, England (and, on paper, Wales) has invested billions in HS2 and has nothing to show for it.

I mean, the project is half-built. That's something to show for it. These things don't happen overnight.

Of course HS2 had a lot of teething problems - which started with the Tories setting it up as a Ltd from scratch instead of getting Network Rail to commission it (they have literally some experience in railways). And then constant political interference and second-guessing the engineers has ballooned the cost further (Bloody Stupid Johnson threw a billion quid worth of work in the bin when he decided to shrink Euston from 11 to 6 platforms to "save money"). Parking the site, refusing to commit to actually building the Euston complex and having people sit on their hands is also not free.

It was telling that when HS2 Ltd were reckoning that Phase 1 would cost £35Bn, insiders at NR were guesstimating ~£45-50Bn just from eyeballing the public information, which was about spot on. 1 If politicos allowed the engineers to get on with it at the speed of engineering, it'd be more or less on time and on budget. Despite politically-motivated cries of crisis and mismanagement, at the point where Sunak cancelled Phase 2a, HS2 Ltd had not touched their contingency fund in 18months. Hardly a project in crisis!

1. Media of course unfairly claims Phase 1 will cost £60Bn+, but this is a misrepresentation - that's "the total amount HS2 Ltd will have spent when Phase 1 opens" - which of course includes a lot of survey work, design, legal and land acquisition for Phase 2a & 2b. It includes the cost of fixed infrastructure overheads like building railheads at aggregate quarries, which will now support 120km of construction instead of 300km - so the entire cost of that infra is apportioned against Phase 1 instead of ~35% of the cost. You also have the massive apprenticeship schemes which have been run to actually train people how to do this, which will now go to waste and we will allow those people to drift off to other sectors instead of rolling them onto subsequent phases. Propotionately speaking, building less costs more.

HS2 had a lot of teething problems

Unfortunately, it makes little economic or operational sense in its current limited form. In terms of passenger capacity to Manchester it may be worse than the present route. It would have done comparatively little for the destinations further away from London with longer journey times and now does nothing (apart from reduce the chances of more modest rail investments in the future). Admittedly there will be more capacity on the WCML between London and Birmingham, but the lack of paths is worst north of Rugby where there will now be no improvement.

I think we're not looking so much at teething problems as the growing tusks of a while elephant.

Half-built is not built and the business case looks shakier than ever, along with spiralling costs.

In my travels around the globe, seen it all before.

In general, there are NO VOTES in well funded, maintained, infrastructure. There are votes in cutting the ribbon on another bridge, road, hostpital, etc. Well, the photo op that such an event brings. Maintenance does not get junkets, kickbacks, freebies, upgrades or the chance to spend money on the politicians pet projects. Photo opportunities get on re-elected and the chance for patronage.

Then, we need to look at the electoral cycle. Often, the electoral cycle dictates the timings to "only things that can be delivered inside the electoral cycle". 1 in a thousang get through to a 2nd cycle, but only if the winner things they are going to get in a second time and they can save this project up for opening just before 2nd election. 'Tis a rare bird indeed that makes it to the 3rd election or beyond, because there are so many things at play.

No politician wants to do the hard work of delivering a project just for the other side to take credit.

I am looking particularly at Australia here where a 3 year federal election cycle means that the federal government follows the cycle of Y1: Blame the previous govt for a budget black hole, Y2: Do nothing and build a war chest and Y3: Make promises to nearly everyone with a magic pot of gold. None, however, is actually spent on REAL projects that help any section of society. State Governments are only a bit better.

The Swiss and the Singaporeans seem to be the only ones that get it right. The Swiss, because the consensus politics is more or less enforced by local democracy (eg, citizens can reject laws and propose their own law and even constitutional amendments). The Singaporeans, because I don't think there will ever be a real change in the ruling party, and they seem to have found that you need infrastructure to make an economy tick (with the profits for the top that that brings in).

Germany is a weird example of public transport done brilliantly and dreadfully.

On the one hand, local S-Bahn and U-Bahn are run by the city or the state (Lander), who have the tax powers to raise funds, and the local interest to invest in such schemes without having to go begging and scraping to Berlin (as UK cities have to with Westminster/Treasury).

These schemes are frequently brilliant, offering reliable and cost-effective local and regional travel.

Nationally however, Deutsche Bahn are a bloody awful, hamstrung no doubt by a lack of investment from the Federal Government, with much of the railway in about the same shape it was following reunification. Going West-East remains markedly more difficult than going North-South, and the bits and bobs of high-speed and rare and interspersed with incredibly slow sections. A train can get up to 160mph and then be back down to 80mph. They've never really built an LGV equivalent, just sped up bits of existing track (or put in some dedicated express lines along a regional line where the corridor allows). Thy do seem to have some unique problems though, including a couple of head-on-collisions (which literally shouldn't be possible - and unlike the recent Cambrian line or Salisbury crashes, these were not a case of a train jumping points because of low adhesion - just two trains running into each other on a track where there should only be one train).

This isn't entirely fair because there are good bits. But the German national network has basically suffered the same disinterest that the UK network has. The only difference is that our local transport is crap as well.

Yes, the situation from the mid-1990s until a few years ago was similar to Britain after The Beeching Report: lines and stations closed and the rest maintained less frequently, if at all – no longer pruning trees was a favorite. 15 - 20 years of that will take 15 - 20 years of more than normal investment to get back to normal. At the time, privatisation was considered the way to open the railways for new investment, just as had happened in the UK… Things aren't helped by a law that enforces a strict per km pricing.

My last few trips have been pretty instense: > 2 hours coming back from Munich; body obstructing the track (yes, I felt the impact), rerouting because of a signal failure, and last week more than 4 hours delay coming back from Berlin due storm damage of the power lines. This could have been compounded with a trip on the local "rail replacement service", but at 1:30 in the morning, I bit the bullet and took the taxi for the last 20 km instead. Really awful but at least we got back and the air conditioning largely did its job. The storm went on the cause even more damage in and around Berlin, and, while some of that was exacerbated by insufficient maintenance, climate change is leading to extremely violent if localised storms, even tornadoes.

My last trip on UK rail was more expensive and involved more than one cancellation with no transfer of seat reservation. Oh what larks!

To be fair, that one was a test for the track, the german record on rails is at 406.9 km/h - from 1988.

One wonders if this was the only track in the whole of Germany that could be used. If this was the UK, it would likely have been tested on the track they used to check locomotives crash testing nuclear waste containers.

https://youtu.be/Zv8xnmOHeCE?si=HxXkhO2CLNefbVK7

I thought exactly the same. But then someone hinted me to [1]OpenRailwayMap . Great site! Click "Max Speeds" in the upper left. And there I saw about three possible candidates. Still sad, but more than one.

[1] https://openrailwaymap.org/

Thanks for that... I never knew it existed. Brilliant.

In practical terms, 300-350km/h is about the maximum for railed vehicles.

Above that, hunting oscillations become a serious issue (perhaps mitigated by gyros but still a major issue) but more importantly the overhead wiring takes an absolute battering from the pantographs and maintenance costs rise sharply as a result

French TGV speed tests required especially modified trains with larger wheels and a full inspection of the track/overheads afterwards

It's less about the trains falling to bits as the infrastructure doing so. Proving you CAN go that fast gives a safety margin at lower speeds

Above that, hunting oscillations become a serious issue (perhaps mitigated by gyros but still a major issue) but more importantly the overhead wiring takes an absolute battering from the pantographs and maintenance costs rise sharply as a result

French TGV speed tests required especially modified trains with larger wheels and a full inspection of the track/overheads afterwards

Yeah, they also increased the wire tension to deal with the high speed run.

The whole track section had to be reconfigured specially, and then put back for normal running.

It's not that you can't do it but as you say, maintenance costs rise rapidly above 250mph.

In fairness, some of this can be alleviated with modern techniques - the French used ballast for much of their LGVs and faster running will smash up the ballast quicker and require more frequent tamping/reballasting. HS2 is using slab track which allows better dimensional rigidity and doesn't settle or need reballasting. This is part of the future proofing (or "gold-plating" depending who you speak to) to potentially run at higher speeds if vehicle design catches up. The HS2 alignment itself is good for >400kmh, but that is as much for passenger comfort and maintenance as anything. If you're building it from scratch, there's no reason not to keep it arrow-straight and give your passengers the best ride. And of course straight tracks require less maintenance than bends, so it's just all-round good design.

What I had not appreciated until I saw the video, is that fast running on a smooth improved track, is just as rattling and jarring as an old train on an old track. They crank the speed up to the new safe limit, and the train jumps and twitches, and the passengers sway and jerk.

Can't help wondering how safe such ultra-fast trains would be if they hit an obstruction on the line or were deliberately derailed by terrorist acts. Vast lengths of line would need to be actively monitored for any suspicious activity.

This question is answered in a number of TGV crash tests - and an inspection of TGV trackside fencing