High Speed Two (HS2) discussion

[HSTEd]

I will note that TVM430 has apparently been used at 150m block lengths before (in the Chunnel, which translates to just under two seconds of travel time at 320kph).

The limitation is not the length of the "blocks" in the system, but that TVM430 can only transmit a fixed (and quite small, only six) number of speeds at any one time. In the case of 300kph rated High speed lines these are 300, 270, 230, 170, 80 and 0.

A more modern communication based system could quite feasibly use more advanced communication technologies (GSM-R with leaky feeders for tunnels) to transmit an integer value for speed, permitting still shorter block lengths and preventing a semi "staircase" system, as even the conventional TVM-430 can only transmit information regarding two blocks ahead.

Additionally TVM-430 does not allow ATO, which would enable the train to be operated closer to the automatic stopping distances as the computer could take control immediately rather than providing a "window of opportunity" for the driver to do something before doing so.

As I understand it the basic architecture of TVM-430 permits the blocks to be made arbitrarily short, permitting them to be made shorter at the approach and "exit" of stations, allowing my proposal to have slow trains interspersed with the fasts using an approximation of moving block working.

 

[Tiny Tim]

I wouldn't doubt HSTEd's latest calculations using Shinkansen type trains and true moving block signalling. The question is if HS2 is going to go for this. There's some time before a committment has to be made. I hope that they're brave enough, but I think it's unlikely.

 

[Nym]

There is no such thing as moving block signalling!

There is virtualised dynamic multi-block signalling with infintecimaly small blocks though.

 

[Tiny Tim]

There is no such thing as moving block signalling!

There is virtualised dynamic multi-block signalling with infintecimaly small blocks though.

Pardon my ignorance.

 

[Nym]

Don't worry, everyone calls it moving block signalling, but that would mean solving the Heisenberg uncertainty principle... You can only know where something going 250mph is to some level of precision and accuracy. Very small blocks would be how it would be implemented. Similar to how the met line used to be set up.

Think 100 aspect signalling and you're getting close.

I'm yet to find someone else who doesn't call it moving block signalling, but it isn't, it's dynamic block signalling.

 

[HSTEd]

The big problem is that track circuits can't be made much shorter than about 150m without starting to get unreliable due to the small number of axles in each block (in theory we could be dealing with two axles every 28 metres for Talgo stock.)

 

[Nym]

Who said I was even considering tack curcits though? I beleive it was in the ERTMS thread I mentioned position calibration balises on the track in combination with speed and distance measuring equipment? You could have them every 25m and be read reliabally.

 

[Crispy75]

Alternatives are as laughable as British triumphs like HOTOL in aerospace

HOTOL lives! Well, the engineers who designed it do, and their engine technology does. Pre-cooler testing is ongoing and if successful will release $350m funding for design and prototyping of the Skylon spaceplane. They're not kidding about - ESA and private finance backing.

http://en.wikipedia.org/wiki/Skylon_(spacecraft)

 

[HSTEd]

Who said I was even considering tack curcits though? I beleive it was in the ERTMS thread I mentioned position calibration balises on the track in combination with speed and distance measuring equipment? You could have them every 25m and be read reliabally.

I'm not, I was explaining one of the limitations of TVM-430, that you cant make the blocks any shorter even if you could solve the speed value issue.

 

[LNW-GW Joint]

HOTOL lives! Well, the engineers who designed it do, and their engine technology does. Pre-cooler testing is ongoing and if successful will release $350m funding for design and prototyping of the Skylon spaceplane. They're not kidding about - ESA and private finance backing.
http://en.wikipedia.org/wiki/Skylon_(spacecraft)

R&D with a limited budget is fine, but you wouldn't want to bet the farm on new technology would you?
That's what Railtrack did with Radio Block Signalling for the WCML. It brought them down and is why the eventual upgrade cost mega-bucks (and still isn't finished).
Talking about new technology for HS2 is a guarantee it will never be built (which suits some people).

 

[Zoe]

Additionally TVM-430 does not allow ATO, which would enable the train to be operated closer to the automatic stopping distances as the computer could take control immediately rather than providing a "window of opportunity" for the driver to do something before doing so.

Is there any reason why ATO is not allowed to be used on this system? TVM-430 itself may not support it but why not allow a separate ATO system to make use of the ATP provided by TVM-430? Is it the case that there would be no way of trasmitting the information from the ATP to the ATO in TVM-430?

 

[HSTEd]

Is there any reason why ATO is not allowed to be used on this system? TVM-430 itself may not support it but why not allow a separate ATO system to make use of the ATP provided by TVM-430? Is it the case that there would be no way of trasmitting the information from the ATP to the ATO in TVM-430?

If your going to implement a control system that uses the information provided by TVM-430, you might as well scrap the TVM-430 and use a system designed from the ground up for largely automatic operation, it simplifies things considerably.

The primary problem with TVM-430 as I said is that it deos not allow for smooth deceleration curves of the kind needed for true moving/dynamic block operation.

 

[dggar]

If Borris Island gets the go ahead (as hinted on the Today programme) will there still be a need for a spur to Heathrow

Could the new royal yatch be used to transfer passengers into the city?

 

[CosherB]

If Borris Island gets the go ahead (as hinted on the Today programme) will there still be a need for a spur to Heathrow

Isn't a spur line off a High Speed railway an oxymoron???

As for Hotol, look at what Branson is doing with Virgin Galactic. Early days yet, but we'll never see another Concorde but may well see much faster air travel than that using sub-orbital space technology.

 

[Chris125]

'Boris Island' would make HS2 look short term, and i expect the consultation will bring all the reasons why it was laughed at back into sharp relief - even Boris started to distance himself from the idea before the latest plan emerged.

Its not the first time an airport out there has been proposed, and i doubt it will be the last...

Chris

 

[Zoe]

'Boris Island' would make HS2 look short term, and i expect the consultation will bring all the reasons why it was laughed at back into sharp relief - even Boris started to distance himself from the idea before the latest plan emerged.

Building a new airport would be short term as air travel is simply not sustainable long term.

 

[CosherB]

Building a new airport would be short term as air travel is simply not sustainable long term.

Really? I tend to agree for short overland journeys (London to Scotland, for example). But are we really going to go back to 6 months in a sailing ship to reach Australia (if we are one of the lucky ones to survive such a journey)?

 

[Zoe]

Really? I tend to agree for short overland journeys (London to Scotland, for example). But are we really going to go back to 6 months in a sailing ship to reach Australia (if we are one of the lucky ones to survive such a journey)?

It's not a great idea at all but with concerns like climate change and peak oil there may simply be no alternative in the long term.

 

[CosherB]

It's not a great idea at all but with concerns like climate change and peak oil there may simply be no alternative in the long term.

There's loads of oil. Fracking promises to deliver more oil than we've had out of the ground to date. True, it will be more expensive to extract so the price will go up, but that won't stop people flying (tyhough it might cut down some of the frivolous low-cost stuff on offer).

 

[Zoe]

There's loads of oil. Fracking promises to deliver more oil than we've had out of the ground to date. True, it will be more expensive to extract so the price will go up, but that won't stop people flying (tyhough it might cut down some of the frivolous low-cost stuff on offer).

What about climate change though?

 

[NSEFAN]

If the train becomes a lot cheaper than flying, then we may well see fewer short-haul flights in the future.

Climate change will have to be managed, but there will be always be people willing to pay the cost of travelling around the world. Hopefully we will develop super-capacitors to power electric planes, but in the meantime we can get people off of flights for short-haul journeys.

 

[jon0844]

What about climate change though?

What about it?

 

[Zoe]

What about it?

Well I think the need to significantly reduce CO2 emissions is obvious and providing more airport capacity is not going to help here.

 

[YorkshireBear]

Not only climate change but the need to lead a more sustainable lifestyle not just using up natural resources wherever possible.

 

[HSTEd]

Really? I tend to agree for short overland journeys (London to Scotland, for example). But are we really going to go back to 6 months in a sailing ship to reach Australia (if we are one of the lucky ones to survive such a journey)?

Well a nuclear powered vessel could make the journey in two weeks assuming it could sustain 30 knots and fitted through Suez, ofcourse the former is rather conservative (if the ship was built for speed, and once you have a nuclear reactor fuel is cheap).

Even going via the Cape of Good Hope is only a couple of extra days and allows you to make the ship huge that it can carry vast quantities of cargo and passengers nad make the transit at higher speeds economically .

Never be viable, but just saying

 

[ainsworth74]

What about climate change though?

I suspect that if we were to curtail all but intercontinental air travel we would be able to continue that without too much danger to the planet (if we could just get the Americans to stop treating domestic air travel like getting a bus it would be a start).

 

[CosherB]

Well I think the need to significantly reduce CO2 emissions is obvious and providing more airport capacity is not going to help here.

Aircraft gas turbine (jet and turboprop) engines are increadilbly efficient, and burn their fuel very cleanly because they operate at very high temperatures compared to car and truck piston engines. Run your finger around the exhaust outlet of a bus and it'll be covered in nasty black stuff. Do the same on a gas turbine exhaust and there'll be no deposit.

The air quality around a major airport will be quite poor - but that almost all generated by the large amount of surface traffic (cars, buses, trucks, and diesel trains) that the airport generates. Very little comes from the aeroplanes (and those long white condesation trails you see in a blue sky are simply water vapour or ice crystals - quite harmless to the environment).

Actually, rail has some of the dirtiest diesels engines around. Some trains make you wonder if steam locos ever left the railway such is the amount of smoke they generate!

 

[Yew]

What about HS3? Through the chunnel, and all the way down to africa? then get a boat to australia

 

[CosherB]

What about HS3? Through the chunnel, and all the way down to africa? then get a boat to australia

HS4... Skytrain! (Anyone remember Freddie Laker?).

 

[imagination]

Aircraft gas turbine (jet and turboprop) engines are increadilbly efficient, and burn their fuel very cleanly because they operate at very high temperatures compared to car and truck piston engines. Run your finger around the exhaust outlet of a bus and it'll be covered in nasty black stuff. Do the same on a gas turbine exhaust and there'll be no deposit.

The problem with aeroplanes isn't so much the amount of emissions they give out as the location of these emissions. A lot of the emissions just above the earth's surface will be absorbed before ever having an impact beyond the local/short term scale, whereas up in the high atmosphere there's pretty much nothing TO absorb them. So the effect is disproportionately high.

Incidentally the main reason why rail engines tend to be dirty is because trains get replaced far less frequently than other modes of transport. A significant proportion of britain's trains are 30+ years old, whereas for cars that figure is extremely low, and for buses I think it's actually illegal. If you consider how much more efficient cars and buses are now than they were 30 years ago, it should put you in a bit of perspective.

And around the oil issue - it isn't just that oil prices will go up, you also have to consider the fact that the quality of the oil is getting (fairly rapidly) worse. This means far more pollution and waste is generated before you even get to use the oil (although some of the waste that is generated in the cracking process can be reused, a lot of it can not and there is already a significant amount generated before that which also can not).

The oil we are turning to as supplies gradually dwindle is increasingly more suitable for making plastics and increasingly less suitable as a fuel source.