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HS2 canal crossing points


Peter-Bullfinch
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7 minutes ago, MJG said:

Well you frequently call others for doing exactly what you do yourself, so glad you finally agree.

 

You know you are SUCH fun to have around. Everyone here is delighted you are back! 

 

<snigger>

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17 hours ago, Sea Dog said:

The thing they somehow fail to mention about HS2 is that it's not really as simple as being about a stupid vanity project to knock minutes off a journey to/from London, but rather there's a major capacity issue. Whist your building an extra railway line, it might as well be a modern, fast one.  Doesn't mean you have to like it though Tim! :)

 

Even assuming that there is a major capacity issue which I seriously doubt HS2 is even trying to address; I understand that the trouble with making it a "modern fast one" is that the running costs are significantly higher. I have seen a figure quoted that HS2 on its own will require around half the capacity of the new Hinkley Point C reactor. - the costs for which haven't been factored into any estimates

 

Additionally making it fast is why the route has to be in straight lines, and with no intermediate stops, or connections with other lines as corners and stations slow down the train; which explains why the route simply bulldozes through so many irreplaceable SSIs etc 

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1 hour ago, KevMc said:

Even assuming that there is a major capacity issue which I seriously doubt HS2 is even trying to address; I understand that the trouble with making it a "modern fast one" is that the running costs are significantly higher. I have seen a figure quoted that HS2 on its own will require around half the capacity of the new Hinkley Point C reactor. - the costs for which haven't been factored into any estimates

 

Additionally making it fast is why the route has to be in straight lines, and with no intermediate stops, or connections with other lines as corners and stations slow down the train; which explains why the route simply bulldozes through so many irreplaceable SSIs etc 

Oh dont worry about the power station thing its all going to be absolutely fine.  Remember the govnmt tells us that in less than nineteen years we will all be running cars on electricity and there will be no fossil fuel cars being built. So there are going to be car charging points soon littering the country using all the excess lectricity up that HS2 doesnt need. Simples.

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5 hours ago, KevMc said:

Even assuming that there is a major capacity issue which I seriously doubt HS2 is even trying to address; I understand that the trouble with making it a "modern fast one" is that the running costs are significantly higher. I have seen a figure quoted that HS2 on its own will require around half the capacity of the new Hinkley Point C reactor. - the costs for which haven't been factored into any estimates

 

Additionally making it fast is why the route has to be in straight lines, and with no intermediate stops, or connections with other lines as corners and stations slow down the train; which explains why the route simply bulldozes through so many irreplaceable SSIs etc 

I never realised that when I paid my electricity bill, as HS2 will have to do, I would have to buy the power station as well!

 

George

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6 hours ago, KevMc said:

I have seen a figure quoted that HS2 on its own will require around half the capacity of the new Hinkley Point C reactor. - the costs for which haven't been factored into any estimates

Let's do the maths, shall we?  According to Wikipedia, the power of a particular type of TGV train is 9.6MW. https://en.wikipedia.org/wiki/SNCF_TGV_POS That's probably a reasonable ball-park for an HS2 high speed train, yes? That's the maximum power, when it's accelerating flat out. The electrical power output of Hinckley C is planned to be 3260MW https://en.wikipedia.org/wiki/Hinkley_Point_C_nuclear_power_station

 

So half the power of Hinckley C is enough to power (3260/2)/9.6 equals 170 HS2 trains, all going flat out, all at the same time, 24/7. Does that sound likely?

 

I'm calling FAKE NEWS.

 

MP.

 

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13 minutes ago, MoominPapa said:

Let's do the maths, shall we?  According to Wikipedia, the power of a particular type of TGV train is 9.6MW. https://en.wikipedia.org/wiki/SNCF_TGV_POS That's probably a reasonable ball-park for an HS2 high speed train, yes? That's the maximum power, when it's accelerating flat out. The electrical power output of Hinckley C is planned to be 3260MW https://en.wikipedia.org/wiki/Hinkley_Point_C_nuclear_power_station

 

So half the power of Hinckley C is enough to power (3260/2)/9.6 equals 170 HS2 trains, all going flat out, all at the same time, 24/7. Does that sound likely?

 

I'm calling FAKE NEWS.

 

MP.

 

Well calculated.  Then of course, electric trains return 20% of the electricity they use back to the wires when braking for other trains to use, something diesel trains and road vehicles cannot do.

 

So that's another 20% to be deducted from HS2 power use.

 

George

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13 minutes ago, furnessvale said:

Well calculated.  Then of course, electric trains return 20% of the electricity they use back to the wires when braking for other trains to use, something diesel trains and road vehicles cannot do.

 

So that's another 20% to be deducted from HS2 power use.

 

George

That energy can only be put to useful work if another train is drawing at least as much power in the same electrical section simultaneously to one that is using the regenerative brakes. If 20% is correct I suspect a good deal of it is dissipated from the overhead wires as heat.

 

That old Virgin Trains TV advert about putting enough power back into the 'grid' to boil however many kettles was very cleverly worded to satisfy the ASA. There is no means of back feeding the National Grid.

 

JP

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7 hours ago, KevMc said:

Even assuming that there is a major capacity issue which I seriously doubt HS2 is even trying to address; I understand that the trouble with making it a "modern fast one" is that the running costs are significantly higher. I have seen a figure quoted that HS2 on its own will require around half the capacity of the new Hinkley Point C reactor. - the costs for which haven't been factored into any estimates

 

Additionally making it fast is why the route has to be in straight lines, and with no intermediate stops, or connections with other lines as corners and stations slow down the train; which explains why the route simply bulldozes through so many irreplaceable SSIs etc 

It's true that if the same number of trains run between the same points the overall power draw for making them go faster will be greater. The balance lies in that the faster the journey the more demand is created and more income to pay for it. Overall this generates a better business case for making it high speed. Technologically there isn't a major step change from conventional to high speed rail. There is a couple of centuries of evidence to demonstrate the economic impact of rail infrastructure projects in the UK and 50 years of high speed rail on our doorstep. It's not high risk providing the country holds it nerve and gets on with it. Delays and scope changes will damage the case.

 

If you were asked to build a railway from A to B would you deliberately make it less straight if the required speed was lower and the curves could be sharper? I think no matter the technology the starting point for a potential route is a straight line.

 

JP

 

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39 minutes ago, MoominPapa said:

Let's do the maths, shall we?  According to Wikipedia, the power of a particular type of TGV train is 9.6MW. https://en.wikipedia.org/wiki/SNCF_TGV_POS That's probably a reasonable ball-park for an HS2 high speed train, yes? That's the maximum power, when it's accelerating flat out. The electrical power output of Hinckley C is planned to be 3260MW https://en.wikipedia.org/wiki/Hinkley_Point_C_nuclear_power_station

 

So half the power of Hinckley C is enough to power (3260/2)/9.6 equals 170 HS2 trains, all going flat out, all at the same time, 24/7. Does that sound likely?

 

I'm calling FAKE NEWS.

 

MP.

 

Can't beat some proper scientific fact.

 

Anyway, something has to provide a base load for the new nuclear stations.

 

JP

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14 minutes ago, Captain Pegg said:

That energy can only be put to useful work if another train is drawing at least as much power in the same electrical section simultaneously to one that is using the regenerative brakes. If 20% is correct I suspect a good deal of it is dissipated from the overhead wires as heat.

 

That old Virgin Trains TV advert about putting enough power back into the 'grid' to boil however many kettles was very cleverly worded to satisfy the ASA. There is no means of back feeding the National Grid.

 

JP

All true but electrical sections on 25kv railways are now very long.

 

For example on the west coast main line.  One feed is at Catterall half way between Preston and Lancaster.  The next one south is at Winwick just north of Warrington.  Plenty of trains in section to absorb the returned juice.

 

George

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32 minutes ago, furnessvale said:

All true but electrical sections on 25kv railways are now very long.

 

For example on the west coast main line.  One feed is at Catterall half way between Preston and Lancaster.  The next one south is at Winwick just north of Warrington.  Plenty of trains in section to absorb the returned juice.

 

George

The sections are about 15 miles each. You've missed one just south of Euxton.

 

Catterall feeds northward to Hest Bank.

Euxton Jn to Catterall is fed from a feeder at Euxton.

Golborne to Euxton is fed from a feeder that I think sits at the intersection of the WCML and Liverpool & Manchester Railway.

The next section to the south is only 12 miles and covers Preston Brook to Winwick.

 

Improving power supplies for increased demand needs shorter sections. The limitation is what the grid can supply. It's one of the capacity constraints that is often overlooked when considering the ability to run longer trains; along with things like platform length and pedflow capability of stations.

 

Energy is recovered, I am not questioning that. I am just sceptical that as much as 20% of that drawn for power is usefully returned. That's a very big number when you consider the relatively small proportion of time a train will spend under braking compared to drawing power and that the energy created has to be used instantaneously. Does your source have good provenance?

 

On HS2 I would also expect the potential for recovery to be lower than the conventional network due to less need to brake.

 

JP

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3 hours ago, Captain Pegg said:

That energy can only be put to useful work if another train is drawing at least as much power in the same electrical section simultaneously to one that is using the regenerative brakes. If 20% is correct I suspect a good deal of it is dissipated from the overhead wires as heat.

 

That old Virgin Trains TV advert about putting enough power back into the 'grid' to boil however many kettles was very cleverly worded to satisfy the ASA. There is no means of back feeding the National Grid.

 

JP

Why is there no means of back feeding the national grid? I don’t know anything about trains, maybe it is all DC? But certainly you can backfeed the national grid from any mains socket. And even if the trains do run on DC, at a pinch an inverter could be used to backfeed the national grid.

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3 minutes ago, nicknorman said:

Why is there no means of back feeding the national grid? I don’t know anything about trains, maybe it is all DC? But certainly you can backfeed the national grid from any mains socket. And even if the trains do run on DC, at a pinch an inverter could be used to backfeed the national grid.

As a non-engineer but someone who has a knowledge, the potential benefit to the national grid over the projected cost of an inverter technlogy over a 5 minute braking period into a station from a moving train would be not financially viable. Having battery storage onboard charged from the braking period to assist leaving a station has value - but again, you have to look at cost of batteries, overall weight of system and whether that power would be any economically better than a straight overhead cable drive fed system.

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12 minutes ago, matty40s said:

As a non-engineer but someone who has a knowledge, the potential benefit to the national grid over the projected cost of an inverter technlogy over a 5 minute braking period into a station from a moving train would be not financially viable. Having battery storage onboard charged from the braking period to assist leaving a station has value - but again, you have to look at cost of batteries, overall weight of system and whether that power would be any economically better than a straight overhead cable drive fed system.

Having done my research I see that overhead power is Ac and 3rd rail power is DC.  HS2 is the former as far as I can tell, so I don’t see why feeding back into the grid would be difficult.

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27 minutes ago, nicknorman said:

Why is there no means of back feeding the national grid? I don’t know anything about trains, maybe it is all DC? But certainly you can backfeed the national grid from any mains socket. And even if the trains do run on DC, at a pinch an inverter could be used to backfeed the national grid.

Supply is 25kV 50Hz AC on the overhead system but historically transformed and rectified to 1500v DC onboard the locomotive. Pretty much all UK mainline electrification pre-dates regenerative braking so it would never have been a consideration.

 

I will consult some folks who will know what modern technology can and does achieve now there are AC traction systems available.

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8 hours ago, Captain Pegg said:

Supply is 25kV 50Hz AC on the overhead system but historically transformed and rectified to 1500v DC onboard the locomotive. Pretty much all UK mainline electrification pre-dates regenerative braking so it would never have been a consideration.

 

I will consult some folks who will know what modern technology can and does achieve now there are AC traction systems available.

So the  issue relates to the guts of the loco, not the track infrastructure. If HS2 is going to have new locos surely it is quite feasible that they’ve incorporated power electronics to feed braking energy back into the overhead lines and hence into the grid?

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33 minutes ago, nicknorman said:

So the  issue relates to the guts of the loco, not the track infrastructure. If HS2 is going to have new locos surely it is quite feasible that they’ve incorporated power electronics to feed braking energy back into the overhead lines and hence into the grid?

The problem, I think, is phase balance. The national grid is three-phase, hence the sets of three cables you see hanging from each side of pylons. Rail traction current is single phase, on a single wire with return through the rails. A feed point consists of a transformer with its primary connected across two grid wires and its secondary connected between the rail and the overhead. This takes power from one phase of the grid, which unbalances the current flowing in the three phases and causes problems if it's too large. Avoiding too large unbalance is a bit of a delicate balance involving no using too large a proportion of the capacity of the grid circuit for rail, different tracks and directions from the feed point on different phases, etc etc. Feeding power unbalanced back into the grid just makes the balancing that much more difficult.

 

MP.

 

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Thank you MP, I did wonder about frequency and phase but it’s not my area of expertise.

 

To be fair to George I support his point it’s just that I believe some of the stuff put out there is misleading and if we want a proper debate of the merits of building HS2 we need proper facts from all sides.

 

One particular use of energy recovery currently being trialled is on board battery storage which gives the capability to either reduce the overall power demand or allow discontinuous electrification so that discrete difficult, expensive to electrify sections can be omitted from an overall scheme. There is still the issue of lugging the weight around which fundamentally undermines the purpose of electrification.

 

JP

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13 hours ago, MoominPapa said:

Let's do the maths, shall we?  According to Wikipedia, the power of a particular type of TGV train is 9.6MW. https://en.wikipedia.org/wiki/SNCF_TGV_POS That's probably a reasonable ball-park for an HS2 high speed train, yes? That's the maximum power, when it's accelerating flat out. The electrical power output of Hinckley C is planned to be 3260MW https://en.wikipedia.org/wiki/Hinkley_Point_C_nuclear_power_station

 

So half the power of Hinckley C is enough to power (3260/2)/9.6 equals 170 HS2 trains, all going flat out, all at the same time, 24/7. Does that sound likely?

 

I'm calling FAKE NEWS.

 

MP.

 

OK ... so I dug around a bit and according to KPMG (https://www.whatdotheyknow.com/request/487395/response/1177578/attach/4/FOI18 2020 Annex A.pdf) HS2 phase 1 & 2a will need 1.2 TWh ... and eventually this will rise to 3TWh (an increase of between 40% and 67% on total electric demand from the rail sector). Now I always get a little confused when we try to convert Wh figures into total demand so I'm sure someone will contradict me and point out the correct comparison but that does look pretty close to 50% of Hinckley Point C (and more once fully operational).

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