david.hill64
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Posts posted by david.hill64
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10 hours ago, corneliuslundie said:
However, I believe that the long term trend is still as I suggested as the number of live births per woman is something like 1.7 which does not lead to replacement of the population
This is also true, but this figure relates to mothers born in the UK. With recent substantial immigration - and I make no judgements on this - mostly of younger people, then there can be growth without further immigration if the fertility rate of the recent arrivals is greater than that of the more established population, which it would appear to be.
So government policy regarding transport needs - including HS2 - healthcare, housing, education etc and the financing of them, are all based on growing population.
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2 hours ago, corneliuslundie said:
Interesting as that contradicts the government statement which I remember reading. That (which I would not now know how to find) stated that the steady increase in life expectancy over the last few years had almost ended because of increasing obesity, type 2 diabetes etc, and that there were signs that it was actually beginning to decrease. The report cited above evidently believes that life expectancy will continue to increase.
However, whatever the scenario, over the long term if births are below "replacement" level then any population increase will depend entirely on immigration.
By the way, I missed two words out in my original post. I should have said "well over 1500 deaths a day"; it is more than 1600 from a rough calculation. But if you assume stable life expectancy of 80 (for simplicity) then one would expect about 825,000 deaths a year. So the current figure of 600,000 is likely to increase.
But all that is rather academic. My original intention was to point out that the numbers of deaths being suggested in the current pandemic are not going to make a significant dent in the population long term. For comparison, although the most recent figure is apparently about 6000, the long term annual death toll through influenza alone is nearer 15,000 (why is it so high when there is a big immunisation programme?), and some of those who die from Covid 19 would, I am afraid, have died during the year from other (underlying) causes.
By the way, many thanks to those who have been following and reporting on the court case.
Jonathan
But as John Tomlinson pointed out, 27% of the forecast increase in population is caused by excess births over deaths. So the current birth rate would appear to be in excess of the death rate.
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2 hours ago, corneliuslundie said:
So it is apparently predicted that total UK population will stabilise and then begin to fall over the next two decades (i think that was the timescale).
Not according to the Office of National Statistics:
4,5% growth to 69.4 million by 2028, passing 70 million by 2031 and up to 72.4 million 25 years from now. The projections have come down a little since 2016 estimates. Noteworthy that the proportion of over 85's will double. These, if wanting to be mobile, are less likely to be driving and will likely desire public transport provision.
Agreed that the pandemic may amend matters.
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Eurostat publishes some interesting stuff: not very historic though.
Typical link here:
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A generic learning point here is that it is always a good idea to build up the coupling rods first and use these as a template to check that the axle bearings are in the correct place. It can be easier to make adjustments to the frames (elongate the holes) than to the rods. Use an alignment aid appropriate to the scale you are working in.
This is often an issue with older designs where the artwork was hand drawn, but rarely so with modern CAD work.
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At Gladiator we are still tying to trade but cannot guarantee being able to post anything. Apologies to all.
Dave and Trisha-
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15 hours ago, The Stationmaster said:
Some Swindon drawings had to be prepared by the draughtsman visiting the erecting shop to examine what had actually been built rather than what the original drawings had said was supposed to be built. This was really a matter of getting detail correct especially for the pipe drawings which,, according to those who'd worked there and one other source (Eric Mountford), were always drawn from the loco rather than from the GA drawings.
And even these days 'As-built' drawings for electrical/pipe installations in equipment rooms rely on seeing what is there rather than what the installation drawings say...........
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3 hours ago, fiftyfour fiftyfour said:
Your doubts regarding a further change were wrong- they did get changed again! The Great Western power cars were further modified so that the brake force was reduced- basically the bogie brakes on the power car went to approx. 3.5 bar maximum no matter how high a brake step was applied. Prior to that (and very contrary to instructions!!) the power car brakes were good enough to stop from 125 without any coaches in the opinion of many drivers.
Thanks for the update: just shows how important it is not to rely on old information.
Do you know why the change was made? Degrading the performance of something is not done lightly.
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6 hours ago, pete_mcfarlane said:
Out of interest, do the short formations have any limitations on their maximum speed due to the reduced brake force available?
We have been here many time before.
Since the power car brakes were changed in the 80's from the original two stage brake using Girling brake discs to the single stage brake using (originally) BSI or latterly Knorr discs, the braking capability of the HST power cars has complied with the braking curve over the whole speed range up to 125mph. (Unless there has been a further change in recent years, which I doubt). As the DM&EE engineer managing the change, I was involved in the tests of back to back power cars on the GW main line that proved the calculations and lab tests to be true. Note that nominally 80% of the brake force is set through the brake discs and 20% through the tread brake. The tread brake is provided to keep the treads conditioned and aid adhesion.
Getting the WR operations team to agree to the test was difficult: they argued that light locomotives had a speed limit lower than line speed. This being driven by the fact that the braking capability of locos varied from barely adequate to barely noticeable. However, it was pointed out that the HST power car was just that: not a loco, so the tests went ahead. The acceleration of a pair of power cars with an enthusiastic footplate crew curious to see what they would do was impressive.
With the original set up the brake force was reduced at high speeds (I think 90mph was the changeover - KenW will remember) and increased below that speed so that a full service brake to rest from 125mph would be done at an average retardation of 0.9m/s/s. At lower initial speeds the average deceleration would be higher (until initial speed was low enough for brake force build up time to be more significant).
With the revised set up the average retardation was constant independent of the initial speed and independent of the number of trailer cars.
So the only reason for limiting the maximum speed of the short formation will be to give an extra braking distance contingency. This would be eminently sensible as the effect of Wheel Slip Protection activity on even a single axle will be more pronounced on a shorter train as the percentage loss of brake force will be greater. There is nominally 300m contingency on level track for 125mph signalling and full service braking. It isn't excessive for a full formation set.
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As a child in the late 60's I once had the pleasure of a school trip to Rev Awdry's house and his version of a model railway based on his books. It was wonderful. I wonder what became of it?
David
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18 hours ago, Ron Ron Ron said:
The Canadian national government didn’t take over or take any share in Bombardier Aeospace, with most of its manufacturing in Canada .....and aeospace was a (the) major component of the group.
Bombardier Transportation, whilst Canadian owned, is based in Berlin, Germany ...so technically a foreign owned German company.....and has production facilities and carries out product development, all over the world.
Actually I think you'll find that although the practical headquarters of Bombardier Transportation is Berlin, the company has its registered HQ for tax purposes in the UK: Bombardier Transportation (Global Holding) UK Ltd. I remember the internal email coming round in 2015 informing staff (including me at the time). It's possible that Brexit might have caused a HQ staff are based in Berlin though. I left BT two years ago.
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Not really surprising: a Bombardier-Siemens tie up seemed likely before the Alstom-Siemens merger was attempted. Siemens might have a chance of surviving against the Chinese in a world market, but both Alstom and Bombardier are vulnerable individually.
The next question will be whether the EU allows it as it will reduce competition within the EU.
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6 hours ago, 30851 said:
When I read an article that says that Pacers use the same chassis as a Leyland bus from the 70's I despair for the stupidity of journalists and realise that you cannot trust anything you read in a newspaper on any topic...............
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There is a German equivalent, the Heberlein brake, still in use on some narrow gauge lines.
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2 hours ago, phil-b259 said:
Energy consumption is easily remedied without the need to scrap the project (or indeed do much as regards construction of the trackbed).
Chop the maximum speed of HS2 back to the French norms of 186mph or 200mph tops and you make big savings across the board when it comes to fitting out said trackbed without compromising any of the benefits HS2 brings.
Simples!
Moreover noise mitigation measures become less costly. I remember the head of the aerodynamics team at BR Research telling me that aerodynamic noise (admittedly only a proportion of noise generated) is proportional to the ninth power of velocity. Just think about that for a moment: running at 225mph rather than 186mph (100m/s rather than 83m/s) increases the aerodynamic part of the noise generated by 500%. Whereas noise generated by the wheel-rail interaction can be absorbed by low level barriers, upper body noise is much more difficult to contain.
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13 hours ago, Pandora said:
Lord Berkeley, his evidence being the proven expertise of Japanese railways of high-speed operation of dedicated lines for passenger trains for a capacity figure of 12 trains per hour.
What is the evidence for a capacity of 18tph on HS2?
Surely the evidence from Japan and SNCF must be heeded in the HS2 case.
Some information on japanese High Speed services
Be very careful when using Shinkanshen as a yardstick for anything. It is an excellent system but the Japanese have a way of presenting statistics that is quite different to western methods.
For example the wiki reference you give refers to the much admired punctuality statistics with average delay 24 seconds including 'natural disasters'. But what it doesn't mention is that JR changes the timetable en-route when 'natural disasters happen. When I was working on the Taiwan High Speed Rail project (essentially Japanese E&M systems) we went on a tour of Shinkansen systems hosted by JR and the suppliers. On one journey from the north to Tokyo it started snowing: speed was reduced because of snow build up around the suspension. Arrival in Tokyo was 40 minutes after the advertised arrival journey time when we boarded. However, officially we were on time: the snow time-table had been invoked en-route. Can you imagine the furore here if we tried that? Sorry no delay payment due: we invoked the 'NR incompetence (insert other cause as you wish) timetable and were actually on time.
It applies to other statistics too: you will read that no passenger has ever been killed on the Shinkanshen. True by JR definition where a passenger is descried as somebody who has successfully boarded or alighted from a train at a station. So the student who was trapped in a door and dragged to his death doesn't count (hadn't boarded successfully) and the few people who fell from open doors between stations are in the trespass statistics as they left the train not at a station.
The JR signalling system is more than capable of supporting more than 12 trains per hour but they choose to limit the number to ensure system resilience.
The Japanese don't use high speed turnouts: one reason is that the overhead line design is limited to 80km/h at turnouts. This adversely affects capacity in a way that would not be an issue with HS2 (assuming a non-Japanese overhead line design). In Taiwan 200km/h turnouts were installed as the original alignment was based on European practice, but these have an 80km/h limit.
I have no doubt that 18tph is achievable with ETCS. I make that statement as a chartered engineer (though not an IRSE member) with more than 40 years' experience including high speed.
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There is a delay with production of the new Bowen Cooke tenders: a new master is being made as the first had some quality issues.
Dave has been hospitalised in Taiwan and will miss the Bristol show this weekend. Trisha will be there.
Dave
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On 16/01/2020 at 15:38, Phil Bullock said:
And you might enjoy this series of photos.
http://www.miac.org.uk/wilkinson1.html#gwr7023
At this time Worcester was one of the few places left on the WR capable of turning out a Castle as it should have been - pride in the job still evident.
Interesting comparing the state of these with those from Horton Road!!!:
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I thought it had gone quiet: I was expecting that after no posting from you for a week we would see the completed Patriot, three wagons, two carriages and a partridge in a pear tree.............bit of a shock to get this news.
Wishing you a full and rapid recovery.
David
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11 hours ago, phil-b259 said:
Equally platform edge doors create complex aerodynamics - once again you try running a freight or non stopping passenger train through them and there will be problems.
I think they are platform screen doors in Crossrail not platform edge doors, but I understand your point.
On the metros that I have worked on through running (usually of trains returning to the depot after the peaks) has not been a problem. Provided the tunnel ventilation system is designed for it the change in the pressure pulse as the train enters/leaves the station box isn't an issue.
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10 hours ago, phil-b259 said:
Construction trains (even if they use UK locos and wagons) will be heavily restricted (e.g. pass through at walking pace) and are a very different proposition to running such trains once the line is open.
It has long been established that you CANNOT have level boarding between UK trains and the platform if the line has to accommodate freight wagons due to clearances.
Such platforms are higher than UK or even EU TSI standards permit and as such are foul of the UK loading gauge - they can only exist where tracks are EXCLUSIVELY used by dedicated passenger stock like the Crossrail core and the East London line.
I wasn't suggesting that freight or indeed anything other than Crossrail stock need use the tunnel when in service and it is certainly true that the 1100 mm platforms would present an obstacle to many types of vehicle. However, the TSI effectively allows UK to do what it wants. DfT's list of UK rail derogations doesn't contain any relating to infrastructure clearances.
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10 hours ago, phil-b259 said:
There was, and still is NO OBLIGATION to change the signalling system after a derogation has been granted regardless of whether we were still an EU member precisely because the conditions which gave rise to the derogation (the physical infrastructure) won't change.
Quite wrong if we had remained in the EU. I suggest you read the derogation.
I agree that it is now moot.
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7 hours ago, phil-b259 said:
The whole 'Interoperability thing' the EU are on about is blown out of the water by platform heights and the use of things like platform edge doors in the core!
Send a freight or passenger train built to standard UK loading gauge (let alone one built to European gauge) down there and it will hit various bits of infrastructure!
Thats why the derogation was easy to get - although it might be standard gauge track, use the standard 25KV OLE - virtually everything else is going to be different (for good reasons - e.g. to reduce stepping distances, level boarding etc)
As for the selection of the 'TrainGuard' system - one VERY compelling reason is at the time of selection, it was very much a 'proven' product - unlike ECTS which was still at an experimental stage and had not been fitted to any line with aspirations for 30TPH.
Phil some speculation in your comment I think. You imply that the central core has been built to a very restricted loading gauge!!!
We seem to have been able to run construction trains and 345's in the tunnels without problems. 345's apparently cope well with standard UK platforms and those in the Crossrail central section. My assumption is that the civil infrastructure in the tunnels conforms to the passenger train and civil works TSI's which themselves contain an opt out to let UK continue to use the existing gauge throughout the system. The electrification works might even conform to the Energy TSI as the use of PSD's will have mitigated part of the risk.
Trainguard: depends on when the choice was made. The argument for the derogation appears to be that the core needed moving block which as you rightly say is not a proven product as ETCS level 3. Hence the moves to allow an ETCS 2/3 hybrid. (Just to say again that Bombardier has supplied a fully functional mixed traffic ETCS level 3 look alike system to Turkmenistan (I think: it's one of the -stans). But it uses TETRA not GSM as the carrier so doesn't count). But Thameslink, which is ETCS level 2 has a 30 TPH design through the central core. Given that if we had remained in the EU, Trainguard would have to be ripped out soon and replaced by ETCS, it would have been more sensible to adopt ETCS level 2 throughout.
Although Trainguard is a proven product, every metro signalling system is tailored to its application. The wording of the derogation implies that a 'communications bearer capable of supporting ETCS' ie GSM radio , shall be installed as part of the initial installation. What isn't clear to me is whether the intention is that GSM should be used as the data carrier for the Trainguard system. If it is, then it is a completely new development of Trainguard which typically uses 2.4GHz and 5.2GHz Wi-Fi signals as the data carrier. Moreover in the application of Trainguard that I am currently assessing, the use of twin frequencies is a cornerstone of the safety case. If Siemens has had to move away from this - and being 6000 miles away from Crossrail I have no idea what they are actually using - it would have been a significant development.
Hindsight is a wonderful thing, but it seems that Crossrail and Thameslink were unaware of what each other was doing. Otherwise we might have had only ETCS and TPWS/AWS as the onboard systems, and saved a fortune.
Finally more comments about the derogation. It permits CBTC to be used until ETCS is capable of supporting ATO (already in use in Thameslink), communications with PSD and auto reverse. The Bangkok skytrain CBTC system is a metro version of ETCS level 2 and already supports both communications with PSD and auto reverse. The conditions for the derogation to end may well exist before Crossrail is commissioned.
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Greater Anglia's Stadler Flirt - Class 745 & 755
in UK Prototype Discussions (not questions!)
Posted
So now almost as reliable as a Pacer!!!